diff --git a/accessible/ipc/PDocAccessible.ipdl b/accessible/ipc/PDocAccessible.ipdl
index 69281b1067e..91d8a824483 100644
--- a/accessible/ipc/PDocAccessible.ipdl
+++ b/accessible/ipc/PDocAccessible.ipdl
@@ -48,28 +48,28 @@ prio(normal upto high) sync protocol PDocAccessible
   manager PBrowser;
 
 parent:
-  Shutdown();
+  async Shutdown();
 
   /*
    * Notify the parent process the document in the child process is firing an
    * event.
    */
-  Event(uint64_t aID, uint32_t type);
-  ShowEvent(ShowEventData data);
-  HideEvent(uint64_t aRootID);
-  StateChangeEvent(uint64_t aID, uint64_t aState, bool aEnabled);
-  CaretMoveEvent(uint64_t aID, int32_t aOffset);
-  TextChangeEvent(uint64_t aID, nsString aStr, int32_t aStart, uint32_t aLen,
-                  bool aIsInsert, bool aFromUser);
+  async Event(uint64_t aID, uint32_t type);
+  async ShowEvent(ShowEventData data);
+  async HideEvent(uint64_t aRootID);
+  async StateChangeEvent(uint64_t aID, uint64_t aState, bool aEnabled);
+  async CaretMoveEvent(uint64_t aID, int32_t aOffset);
+  async TextChangeEvent(uint64_t aID, nsString aStr, int32_t aStart, uint32_t aLen,
+                        bool aIsInsert, bool aFromUser);
 
   /*
    * Tell the parent document to bind the existing document as a new child
    * document.
    */
-  BindChildDoc(PDocAccessible aChildDoc, uint64_t aID);
+  async BindChildDoc(PDocAccessible aChildDoc, uint64_t aID);
 
 child:
-  __delete__();
+  async __delete__();
 
   // Accessible
   prio(high) sync State(uint64_t aID) returns(uint64_t states);
@@ -132,13 +132,13 @@ child:
   prio(high) sync RemoveFromSelection(uint64_t aID, int32_t aSelectionNum)
     returns(bool aSucceeded);
 
-  ScrollSubstringTo(uint64_t aID, int32_t aStartOffset, int32_t aEndOffset,
-                    uint32_t aScrollType);
-  ScrollSubstringToPoint(uint64_t aID,
-                         int32_t aStartOffset,
-                         int32_t aEndOffset,
-                         uint32_t aCoordinateType,
-                         int32_t aX, int32_t aY);
+  async ScrollSubstringTo(uint64_t aID, int32_t aStartOffset, int32_t aEndOffset,
+                          uint32_t aScrollType);
+  async ScrollSubstringToPoint(uint64_t aID,
+                               int32_t aStartOffset,
+                               int32_t aEndOffset,
+                               uint32_t aCoordinateType,
+                               int32_t aX, int32_t aY);
 
   prio(high) sync Text(uint64_t aID) returns(nsString aText);
   prio(high) sync ReplaceText(uint64_t aID, nsString aText);
diff --git a/devtools/shared/heapsnapshot/PHeapSnapshotTempFileHelper.ipdl b/devtools/shared/heapsnapshot/PHeapSnapshotTempFileHelper.ipdl
index 4f7ad103e76..2576470e255 100644
--- a/devtools/shared/heapsnapshot/PHeapSnapshotTempFileHelper.ipdl
+++ b/devtools/shared/heapsnapshot/PHeapSnapshotTempFileHelper.ipdl
@@ -28,7 +28,7 @@ sync protocol PHeapSnapshotTempFileHelper
 parent:
     sync OpenHeapSnapshotTempFile() returns (OpenHeapSnapshotTempFileResponse response);
 
-    __delete__();
+    async __delete__();
 };
 
 } // namespace devtools
diff --git a/dom/asmjscache/PAsmJSCacheEntry.ipdl b/dom/asmjscache/PAsmJSCacheEntry.ipdl
index 13ebb9b5838..4980650ccb7 100644
--- a/dom/asmjscache/PAsmJSCacheEntry.ipdl
+++ b/dom/asmjscache/PAsmJSCacheEntry.ipdl
@@ -19,18 +19,18 @@ protocol PAsmJSCacheEntry
   // origin's Metadata so the child process can select the cache entry to open
   // (based on hash) and notify the parent (via SelectCacheFileToRead).
 child:
-  OnOpenMetadataForRead(Metadata metadata);
+  async OnOpenMetadataForRead(Metadata metadata);
 parent:
-  SelectCacheFileToRead(uint32_t moduleIndex);
-  CacheMiss();
+  async SelectCacheFileToRead(uint32_t moduleIndex);
+  async CacheMiss();
 
 child:
   // Once the cache file has been opened, the child is notified and sent an
   // open file descriptor.
-  OnOpenCacheFile(int64_t fileSize, FileDescriptor fileDesc);
+  async OnOpenCacheFile(int64_t fileSize, FileDescriptor fileDesc);
 
 both:
-  __delete__(AsmJSCacheResult result);
+  async __delete__(AsmJSCacheResult result);
 };
 
 } // namespace asmjscache
diff --git a/dom/bluetooth/ipc/PBluetooth.ipdl b/dom/bluetooth/ipc/PBluetooth.ipdl
index f9a165590cb..beb8a7f1fc3 100644
--- a/dom/bluetooth/ipc/PBluetooth.ipdl
+++ b/dom/bluetooth/ipc/PBluetooth.ipdl
@@ -545,53 +545,53 @@ child:
   /**
    * Sent when a settings change has enabled or disabled the bluetooth firmware.
    */
-  Enabled(bool enabled);
+  async Enabled(bool enabled);
 
   /**
    * Sent when a bluetooth signal is broadcasted to child processes.
    */
-  Notify(BluetoothSignal signal);
+  async Notify(BluetoothSignal signal);
 
   /**
    * Sent when the parent process is about to be shut down. See shutdown note
    * above.
    */
-  BeginShutdown();
+  async BeginShutdown();
 
   /**
    * Sent to inform the child process that it will no longer receive any
    * messages from the parent. See shutdown note above.
    */
-  NotificationsStopped();
+  async NotificationsStopped();
 
 parent:
   /**
    * Sent when the child no longer needs to use bluetooth. See shutdown note
    * above.
    */
-  __delete__();
+  async __delete__();
 
   /**
    * Sent when the child needs to receive signals related to the given node.
    */
-  RegisterSignalHandler(nsString node);
+  async RegisterSignalHandler(nsString node);
 
   /**
    * Sent when the child no longer needs to receive signals related to the given
    * node.
    */
-  UnregisterSignalHandler(nsString node);
+  async UnregisterSignalHandler(nsString node);
 
   /**
    * Sent when the child no longer needs to receive any messages from the
    * parent. See shutdown note above.
    */
-  StopNotifying();
+  async StopNotifying();
 
   /**
    * Sent when the child makes an asynchronous request to the parent.
    */
-  PBluetoothRequest(Request request);
+  async PBluetoothRequest(Request request);
 
   /**
    * FIXME: Bug 547703.
diff --git a/dom/bluetooth/ipc/PBluetoothRequest.ipdl b/dom/bluetooth/ipc/PBluetoothRequest.ipdl
index 25fb701fb59..c15b9d522a3 100644
--- a/dom/bluetooth/ipc/PBluetoothRequest.ipdl
+++ b/dom/bluetooth/ipc/PBluetoothRequest.ipdl
@@ -20,7 +20,7 @@ child:
   /**
    * Sent when the asynchronous request has completed.
    */
-  __delete__(BluetoothReply response);
+  async __delete__(BluetoothReply response);
 };
 
 } // namespace bluetooth
diff --git a/dom/broadcastchannel/PBroadcastChannel.ipdl b/dom/broadcastchannel/PBroadcastChannel.ipdl
index e06115092b2..4b4a5310676 100644
--- a/dom/broadcastchannel/PBroadcastChannel.ipdl
+++ b/dom/broadcastchannel/PBroadcastChannel.ipdl
@@ -17,12 +17,12 @@ protocol PBroadcastChannel
   manager PBackground;
 
 parent:
-  PostMessage(ClonedMessageData message);
-  Close();
+  async PostMessage(ClonedMessageData message);
+  async Close();
 
 child:
-  Notify(ClonedMessageData message);
-  __delete__();
+  async Notify(ClonedMessageData message);
+  async __delete__();
 };
 
 } // namespace dom
diff --git a/dom/cache/PCache.ipdl b/dom/cache/PCache.ipdl
index fe82c0e6259..29415f12231 100644
--- a/dom/cache/PCache.ipdl
+++ b/dom/cache/PCache.ipdl
@@ -22,12 +22,12 @@ protocol PCache
   manages PCachePushStream;
 
 parent:
-  PCacheOp(CacheOpArgs aOpArgs);
-  PCachePushStream();
-  Teardown();
+  async PCacheOp(CacheOpArgs aOpArgs);
+  async PCachePushStream();
+  async Teardown();
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace cache
diff --git a/dom/cache/PCacheOp.ipdl b/dom/cache/PCacheOp.ipdl
index 7349d47632c..a9a69cedf20 100644
--- a/dom/cache/PCacheOp.ipdl
+++ b/dom/cache/PCacheOp.ipdl
@@ -21,7 +21,7 @@ protocol PCacheOp
   manager PCache or PCacheStorage;
 
 child:
-  __delete__(ErrorResult aRv, CacheOpResult aResult);
+  async __delete__(ErrorResult aRv, CacheOpResult aResult);
 };
 
 } // namespace cache
diff --git a/dom/cache/PCachePushStream.ipdl b/dom/cache/PCachePushStream.ipdl
index 26e7c7b2c84..0553e488b33 100644
--- a/dom/cache/PCachePushStream.ipdl
+++ b/dom/cache/PCachePushStream.ipdl
@@ -13,14 +13,14 @@ protocol PCachePushStream
   manager PCache;
 
 parent:
-  Buffer(nsCString aBuffer);
-  Close(nsresult aRv);
+  async Buffer(nsCString aBuffer);
+  async Close(nsresult aRv);
 
 child:
   // Stream is always destroyed from the parent side.  This occurs if the
   // parent encounters an error while writing to its pipe or if the child
   // signals the stream should close by SendClose().
-  __delete__();
+  async __delete__();
 };
 
 } // namespace cache
diff --git a/dom/cache/PCacheStorage.ipdl b/dom/cache/PCacheStorage.ipdl
index fa11de48fbc..3635d5aec88 100644
--- a/dom/cache/PCacheStorage.ipdl
+++ b/dom/cache/PCacheStorage.ipdl
@@ -22,11 +22,11 @@ protocol PCacheStorage
   manages PCacheOp;
 
 parent:
-  PCacheOp(CacheOpArgs aOpArgs);
-  Teardown();
+  async PCacheOp(CacheOpArgs aOpArgs);
+  async Teardown();
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace cache
diff --git a/dom/cache/PCacheStreamControl.ipdl b/dom/cache/PCacheStreamControl.ipdl
index 21155584b25..f42b8f9e4f8 100644
--- a/dom/cache/PCacheStreamControl.ipdl
+++ b/dom/cache/PCacheStreamControl.ipdl
@@ -15,12 +15,12 @@ protocol PCacheStreamControl
   manager PBackground;
 
 parent:
-  NoteClosed(nsID aStreamId);
+  async NoteClosed(nsID aStreamId);
 
 child:
-  Close(nsID aStreamId);
-  CloseAll();
-  __delete__();
+  async Close(nsID aStreamId);
+  async CloseAll();
+  async __delete__();
 };
 
 } // namespace cache
diff --git a/dom/cellbroadcast/ipc/PCellBroadcast.ipdl b/dom/cellbroadcast/ipc/PCellBroadcast.ipdl
index 9a6aa4e612f..26e0c1e7f07 100644
--- a/dom/cellbroadcast/ipc/PCellBroadcast.ipdl
+++ b/dom/cellbroadcast/ipc/PCellBroadcast.ipdl
@@ -14,28 +14,28 @@ sync protocol PCellBroadcast {
   manager PContent;
 
 child:
-  NotifyReceivedMessage(uint32_t aServiceId,
-                        uint32_t aGsmGeographicalScope,
-                        uint16_t aMessageCode,
-                        uint16_t aMessageId,
-                        nsString aLanguage,
-                        nsString aBody,
-                        uint32_t aMessageClass,
-                        uint64_t aTimestamp,
-                        uint32_t aCdmaServiceCategory,
-                        bool aHasEtwsInfo,
-                        uint32_t aEtwsWarningType,
-                        bool aEtwsEmergencyUserAlert,
-                        bool aEtwsPopup);
+  async NotifyReceivedMessage(uint32_t aServiceId,
+                              uint32_t aGsmGeographicalScope,
+                              uint16_t aMessageCode,
+                              uint16_t aMessageId,
+                              nsString aLanguage,
+                              nsString aBody,
+                              uint32_t aMessageClass,
+                              uint64_t aTimestamp,
+                              uint32_t aCdmaServiceCategory,
+                              bool aHasEtwsInfo,
+                              uint32_t aEtwsWarningType,
+                              bool aEtwsEmergencyUserAlert,
+                              bool aEtwsPopup);
 
 parent:
   /**
    * Sent when the child no longer needs to use cellbroadcast.
    */
-  __delete__();
+  async __delete__();
 
 };
 
 } // namespace mobilemessage
 } // namespace dom
-} // namespace cellbroadcast
\ No newline at end of file
+} // namespace cellbroadcast
diff --git a/dom/devicestorage/PDeviceStorageRequest.ipdl b/dom/devicestorage/PDeviceStorageRequest.ipdl
index f85d7fcbaec..5351311e44f 100644
--- a/dom/devicestorage/PDeviceStorageRequest.ipdl
+++ b/dom/devicestorage/PDeviceStorageRequest.ipdl
@@ -85,7 +85,7 @@ union DeviceStorageResponseValue
 sync protocol PDeviceStorageRequest {
     manager PContent;
 child:
-    __delete__(DeviceStorageResponseValue response);
+    async __delete__(DeviceStorageResponseValue response);
 };
 
 } // namespace devicestorage
diff --git a/dom/filehandle/PBackgroundFileHandle.ipdl b/dom/filehandle/PBackgroundFileHandle.ipdl
index 02d251b8e72..60fdfafbf21 100644
--- a/dom/filehandle/PBackgroundFileHandle.ipdl
+++ b/dom/filehandle/PBackgroundFileHandle.ipdl
@@ -74,17 +74,17 @@ protocol PBackgroundFileHandle
   manages PBackgroundFileRequest;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  Finish();
-  Abort();
+  async Finish();
+  async Abort();
 
-  PBackgroundFileRequest(FileRequestParams params);
+  async PBackgroundFileRequest(FileRequestParams params);
 
 child:
-  __delete__();
+  async __delete__();
 
-  Complete(bool aborted);
+  async Complete(bool aborted);
 };
 
 } // namespace dom
diff --git a/dom/filehandle/PBackgroundFileRequest.ipdl b/dom/filehandle/PBackgroundFileRequest.ipdl
index e43fb67b21f..9fb678b75e5 100644
--- a/dom/filehandle/PBackgroundFileRequest.ipdl
+++ b/dom/filehandle/PBackgroundFileRequest.ipdl
@@ -73,10 +73,10 @@ protocol PBackgroundFileRequest
   manager PBackgroundFileHandle;
 
 child:
-  __delete__(FileRequestResponse response);
+  async __delete__(FileRequestResponse response);
 
-  Progress(uint64_t progress,
-           uint64_t progressMax);
+  async Progress(uint64_t progress,
+                 uint64_t progressMax);
 };
 
 } // namespace dom
diff --git a/dom/filehandle/PBackgroundMutableFile.ipdl b/dom/filehandle/PBackgroundMutableFile.ipdl
index 762c65f1213..0f87f3b6d5d 100644
--- a/dom/filehandle/PBackgroundMutableFile.ipdl
+++ b/dom/filehandle/PBackgroundMutableFile.ipdl
@@ -20,16 +20,16 @@ sync protocol PBackgroundMutableFile
   manages PBackgroundFileHandle;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  PBackgroundFileHandle(FileMode mode);
+  async PBackgroundFileHandle(FileMode mode);
 
   // Use only for testing!
   sync GetFileId()
     returns (int64_t fileId);
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace dom
diff --git a/dom/filesystem/PFileSystemRequest.ipdl b/dom/filesystem/PFileSystemRequest.ipdl
index b1b20beff3a..9e9a7c71c0c 100644
--- a/dom/filesystem/PFileSystemRequest.ipdl
+++ b/dom/filesystem/PFileSystemRequest.ipdl
@@ -49,7 +49,7 @@ sync protocol PFileSystemRequest
   manager PContent;
 
 child:
-  __delete__(FileSystemResponseValue response);
+  async __delete__(FileSystemResponseValue response);
 };
 
 } // namespace dom
diff --git a/dom/fmradio/ipc/PFMRadio.ipdl b/dom/fmradio/ipc/PFMRadio.ipdl
index f4929cfe70b..fdd11bea11e 100644
--- a/dom/fmradio/ipc/PFMRadio.ipdl
+++ b/dom/fmradio/ipc/PFMRadio.ipdl
@@ -71,37 +71,37 @@ child:
   /**
    * Sent when the frequency is changed.
    */
-  NotifyFrequencyChanged(double frequency);
+  async NotifyFrequencyChanged(double frequency);
   /**
    * Sent when the power state of FM radio HW is changed.
    */
-  NotifyEnabledChanged(bool enabled, double frequency);
+  async NotifyEnabledChanged(bool enabled, double frequency);
   /**
    * Sent when RDS is enabled or disabled.
    */
-  NotifyRDSEnabledChanged(bool enabled);
+  async NotifyRDSEnabledChanged(bool enabled);
   /**
    * Sent when we have a new PI code.
    */
-  NotifyPIChanged(bool valid, uint16_t code);
+  async NotifyPIChanged(bool valid, uint16_t code);
   /**
    * Sent when we have a new PTY
    */
-  NotifyPTYChanged(bool valid, uint8_t pty);
+  async NotifyPTYChanged(bool valid, uint8_t pty);
   /**
    * Sent when we have a new PS name.
    */
-  NotifyPSChanged(nsString psname);
+  async NotifyPSChanged(nsString psname);
   /**
    * Sent when we have new radiotext.
    */
-  NotifyRadiotextChanged(nsString radiotext);
+  async NotifyRadiotextChanged(nsString radiotext);
   /**
    * Sent when a full RDS group is received.
    */
-  NotifyNewRDSGroup(uint64_t data);
+  async NotifyNewRDSGroup(uint64_t data);
 
-  __delete__();
+  async __delete__();
 
 parent:
   /**
@@ -119,17 +119,17 @@ parent:
    * on web content, otherwise, we have to do the mapping stuff manually which
    * is more error prone.
    */
-  PFMRadioRequest(FMRadioRequestArgs requestType);
+  async PFMRadioRequest(FMRadioRequestArgs requestType);
 
   /**
    * Enable/Disable audio
    */
-  EnableAudio(bool audioEnabled);
+  async EnableAudio(bool audioEnabled);
 
   /**
    * Set RDS group mask
    */
-  SetRDSGroupMask(uint32_t groupMask);
+  async SetRDSGroupMask(uint32_t groupMask);
 };
 
 } // namespace dom
diff --git a/dom/fmradio/ipc/PFMRadioRequest.ipdl b/dom/fmradio/ipc/PFMRadioRequest.ipdl
index 4a456b0e8c6..d68b6748fb9 100644
--- a/dom/fmradio/ipc/PFMRadioRequest.ipdl
+++ b/dom/fmradio/ipc/PFMRadioRequest.ipdl
@@ -35,7 +35,7 @@ async protocol PFMRadioRequest
   manager PFMRadio;
 
 child:
-  __delete__(FMRadioResponseType response);
+  async __delete__(FMRadioResponseType response);
 };
 
 } // namespace dom
diff --git a/dom/icc/ipc/PIcc.ipdl b/dom/icc/ipc/PIcc.ipdl
index 3a264a102d8..fdad3f3e04a 100644
--- a/dom/icc/ipc/PIcc.ipdl
+++ b/dom/icc/ipc/PIcc.ipdl
@@ -94,12 +94,12 @@ child:
   /**
    * Notify CardStateChanged with updated CardState.
    */
-  NotifyCardStateChanged(uint32_t aCardState);
+  async NotifyCardStateChanged(uint32_t aCardState);
 
   /**
    * Notify IccInfoChanged with updated IccInfo.
    */
-  NotifyIccInfoChanged(OptionalIccInfoData aInfoData);
+  async NotifyIccInfoChanged(OptionalIccInfoData aInfoData);
 
   /**
    * Notify STK proactive command issue by selected UICC.
@@ -107,23 +107,23 @@ child:
    * @param aStkProactiveCmd
    *        a MozStkCommand instance serialized in JSON.
    */
-  NotifyStkCommand(nsString aStkProactiveCmd);
+  async NotifyStkCommand(nsString aStkProactiveCmd);
 
   /**
    * Notify that STK session is ended by selected UICC.
    */
-  NotifyStkSessionEnd();
+  async NotifyStkSessionEnd();
 
 parent:
   /**
    * Sent when the child no longer needs to use PIcc.
    */
-  __delete__();
+  async __delete__();
 
   /**
    * Sent when the child makes an asynchronous request to the parent.
    */
-  PIccRequest(IccRequest aRequest);
+  async PIccRequest(IccRequest aRequest);
 
   /**
    * Send STK response to the selected UICC.
@@ -133,17 +133,17 @@ parent:
    * @param aResponse
    *        a MozStkResponse instance serialized in JSON.
    */
-  StkResponse(nsString aCommand, nsString aResponse);
+  async StkResponse(nsString aCommand, nsString aResponse);
 
   /**
    * Send STK Menu Selection to the selected UICC.
    */
-  StkMenuSelection(uint16_t aItemIdentifier, bool aHelpRequested);
+  async StkMenuSelection(uint16_t aItemIdentifier, bool aHelpRequested);
 
   /**
    * Send STK Timer Expiration to the selected UICC.
    */
-  StkTimerExpiration(uint16_t aTimerId, uint32_t aTimerValue);
+  async StkTimerExpiration(uint16_t aTimerId, uint32_t aTimerValue);
 
   /**
    * Send STK Event Download to the selected UICC.
@@ -151,7 +151,7 @@ parent:
    * @param aEvent
    *        a MozStkXxxEvent instance serialized in JSON.
    */
-  StkEventDownload(nsString aEvent);
+  async StkEventDownload(nsString aEvent);
 
   /**
    * Sync call to initialize the updated IccInfo/CardState.
diff --git a/dom/icc/ipc/PIccRequest.ipdl b/dom/icc/ipc/PIccRequest.ipdl
index 5c8ab1f38ca..275d23d305f 100644
--- a/dom/icc/ipc/PIccRequest.ipdl
+++ b/dom/icc/ipc/PIccRequest.ipdl
@@ -65,7 +65,7 @@ child:
   /**
    * Sent when the asynchronous request has completed.
    */
-  __delete__(IccReply response);
+  async __delete__(IccReply response);
 };
 
 } // namespace icc
diff --git a/dom/indexedDB/PBackgroundIDBCursor.ipdl b/dom/indexedDB/PBackgroundIDBCursor.ipdl
index 5173b2fa0b9..255467891a4 100644
--- a/dom/indexedDB/PBackgroundIDBCursor.ipdl
+++ b/dom/indexedDB/PBackgroundIDBCursor.ipdl
@@ -78,14 +78,14 @@ protocol PBackgroundIDBCursor
   manager PBackgroundIDBTransaction or PBackgroundIDBVersionChangeTransaction;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  Continue(CursorRequestParams params, Key key);
+  async Continue(CursorRequestParams params, Key key);
 
 child:
-  __delete__();
+  async __delete__();
 
-  Response(CursorResponse response);
+  async Response(CursorResponse response);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBDatabase.ipdl b/dom/indexedDB/PBackgroundIDBDatabase.ipdl
index 6c0fa2052e5..dc7d53a83de 100644
--- a/dom/indexedDB/PBackgroundIDBDatabase.ipdl
+++ b/dom/indexedDB/PBackgroundIDBDatabase.ipdl
@@ -53,31 +53,31 @@ sync protocol PBackgroundIDBDatabase
   manages PBackgroundMutableFile;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  Blocked();
+  async Blocked();
 
-  Close();
+  async Close();
 
-  PBackgroundIDBDatabaseFile(PBlob blob);
+  async PBackgroundIDBDatabaseFile(PBlob blob);
 
-  PBackgroundIDBDatabaseRequest(DatabaseRequestParams params);
+  async PBackgroundIDBDatabaseRequest(DatabaseRequestParams params);
 
-  PBackgroundIDBTransaction(nsString[] objectStoreNames, Mode mode);
+  async PBackgroundIDBTransaction(nsString[] objectStoreNames, Mode mode);
 
 child:
-  __delete__();
+  async __delete__();
 
-  VersionChange(uint64_t oldVersion, NullableVersion newVersion);
+  async VersionChange(uint64_t oldVersion, NullableVersion newVersion);
 
-  Invalidate();
+  async Invalidate();
 
-  PBackgroundIDBVersionChangeTransaction(uint64_t currentVersion,
-                                         uint64_t requestedVersion,
-                                         int64_t nextObjectStoreId,
-                                         int64_t nextIndexId);
+  async PBackgroundIDBVersionChangeTransaction(uint64_t currentVersion,
+                                               uint64_t requestedVersion,
+                                               int64_t nextObjectStoreId,
+                                               int64_t nextIndexId);
 
-  PBackgroundMutableFile(nsString name, nsString type);
+  async PBackgroundMutableFile(nsString name, nsString type);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBDatabaseFile.ipdl b/dom/indexedDB/PBackgroundIDBDatabaseFile.ipdl
index db66e773394..e2f7c9f85b1 100644
--- a/dom/indexedDB/PBackgroundIDBDatabaseFile.ipdl
+++ b/dom/indexedDB/PBackgroundIDBDatabaseFile.ipdl
@@ -13,7 +13,7 @@ protocol PBackgroundIDBDatabaseFile
   manager PBackgroundIDBDatabase;
 
 parent:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBDatabaseRequest.ipdl b/dom/indexedDB/PBackgroundIDBDatabaseRequest.ipdl
index ff02bda80c7..c3b342048a1 100644
--- a/dom/indexedDB/PBackgroundIDBDatabaseRequest.ipdl
+++ b/dom/indexedDB/PBackgroundIDBDatabaseRequest.ipdl
@@ -25,7 +25,7 @@ protocol PBackgroundIDBDatabaseRequest
   manager PBackgroundIDBDatabase;
 
 child:
-  __delete__(DatabaseRequestResponse response);
+  async __delete__(DatabaseRequestResponse response);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBFactory.ipdl b/dom/indexedDB/PBackgroundIDBFactory.ipdl
index ff186eff58b..e6c64dca4e0 100644
--- a/dom/indexedDB/PBackgroundIDBFactory.ipdl
+++ b/dom/indexedDB/PBackgroundIDBFactory.ipdl
@@ -49,17 +49,17 @@ sync protocol PBackgroundIDBFactory
   manages PBackgroundIDBFactoryRequest;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  PBackgroundIDBFactoryRequest(FactoryRequestParams params);
+  async PBackgroundIDBFactoryRequest(FactoryRequestParams params);
 
-  IncrementLoggingRequestSerialNumber();
+  async IncrementLoggingRequestSerialNumber();
 
 child:
-  __delete__();
+  async __delete__();
 
-  PBackgroundIDBDatabase(DatabaseSpec spec,
-                         PBackgroundIDBFactoryRequest request);
+  async PBackgroundIDBDatabase(DatabaseSpec spec,
+                               PBackgroundIDBFactoryRequest request);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBFactoryRequest.ipdl b/dom/indexedDB/PBackgroundIDBFactoryRequest.ipdl
index 1e198fc96bb..fc74807fed5 100644
--- a/dom/indexedDB/PBackgroundIDBFactoryRequest.ipdl
+++ b/dom/indexedDB/PBackgroundIDBFactoryRequest.ipdl
@@ -33,14 +33,14 @@ protocol PBackgroundIDBFactoryRequest
   manager PBackgroundIDBFactory;
 
 child:
-  __delete__(FactoryRequestResponse response);
+  async __delete__(FactoryRequestResponse response);
 
-  PermissionChallenge(PrincipalInfo principalInfo);
+  async PermissionChallenge(PrincipalInfo principalInfo);
 
-  Blocked(uint64_t currentVersion);
+  async Blocked(uint64_t currentVersion);
 
 parent:
-  PermissionRetry();
+  async PermissionRetry();
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBRequest.ipdl b/dom/indexedDB/PBackgroundIDBRequest.ipdl
index 694426c2c29..34a30a83342 100644
--- a/dom/indexedDB/PBackgroundIDBRequest.ipdl
+++ b/dom/indexedDB/PBackgroundIDBRequest.ipdl
@@ -105,7 +105,7 @@ protocol PBackgroundIDBRequest
   manager PBackgroundIDBTransaction or PBackgroundIDBVersionChangeTransaction;
 
 child:
-  __delete__(RequestResponse response);
+  async __delete__(RequestResponse response);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBTransaction.ipdl b/dom/indexedDB/PBackgroundIDBTransaction.ipdl
index ba3faafcabd..355f07761c9 100644
--- a/dom/indexedDB/PBackgroundIDBTransaction.ipdl
+++ b/dom/indexedDB/PBackgroundIDBTransaction.ipdl
@@ -22,19 +22,19 @@ protocol PBackgroundIDBTransaction
   manages PBackgroundIDBRequest;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  Commit();
-  Abort(nsresult resultCode);
+  async Commit();
+  async Abort(nsresult resultCode);
 
-  PBackgroundIDBCursor(OpenCursorParams params);
+  async PBackgroundIDBCursor(OpenCursorParams params);
 
-  PBackgroundIDBRequest(RequestParams params);
+  async PBackgroundIDBRequest(RequestParams params);
 
 child:
-  __delete__();
+  async __delete__();
 
-  Complete(nsresult result);
+  async Complete(nsresult result);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIDBVersionChangeTransaction.ipdl b/dom/indexedDB/PBackgroundIDBVersionChangeTransaction.ipdl
index 766e922b79d..1dea5993620 100644
--- a/dom/indexedDB/PBackgroundIDBVersionChangeTransaction.ipdl
+++ b/dom/indexedDB/PBackgroundIDBVersionChangeTransaction.ipdl
@@ -23,27 +23,27 @@ protocol PBackgroundIDBVersionChangeTransaction
   manages PBackgroundIDBRequest;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
-  Commit();
-  Abort(nsresult resultCode);
+  async Commit();
+  async Abort(nsresult resultCode);
 
-  CreateObjectStore(ObjectStoreMetadata metadata);
-  DeleteObjectStore(int64_t objectStoreId);
+  async CreateObjectStore(ObjectStoreMetadata metadata);
+  async DeleteObjectStore(int64_t objectStoreId);
 
-  CreateIndex(int64_t objectStoreId,
-              IndexMetadata metadata);
-  DeleteIndex(int64_t objectStoreId,
-              int64_t indexId);
+  async CreateIndex(int64_t objectStoreId,
+                    IndexMetadata metadata);
+  async DeleteIndex(int64_t objectStoreId,
+                    int64_t indexId);
 
-  PBackgroundIDBCursor(OpenCursorParams params);
+  async PBackgroundIDBCursor(OpenCursorParams params);
 
-  PBackgroundIDBRequest(RequestParams params);
+  async PBackgroundIDBRequest(RequestParams params);
 
 child:
-  __delete__();
+  async __delete__();
 
-  Complete(nsresult result);
+  async Complete(nsresult result);
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PBackgroundIndexedDBUtils.ipdl b/dom/indexedDB/PBackgroundIndexedDBUtils.ipdl
index ba65da24320..aac20e1a445 100644
--- a/dom/indexedDB/PBackgroundIndexedDBUtils.ipdl
+++ b/dom/indexedDB/PBackgroundIndexedDBUtils.ipdl
@@ -18,7 +18,7 @@ sync protocol PBackgroundIndexedDBUtils
   manager PBackground;
 
 parent:
-  DeleteMe();
+  async DeleteMe();
 
   // Use only for testing!
   sync GetFileReferences(PersistenceType persistenceType,
@@ -29,7 +29,7 @@ parent:
              bool result);
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace indexedDB
diff --git a/dom/indexedDB/PIndexedDBPermissionRequest.ipdl b/dom/indexedDB/PIndexedDBPermissionRequest.ipdl
index 4eecb2b1c0a..779793731e4 100644
--- a/dom/indexedDB/PIndexedDBPermissionRequest.ipdl
+++ b/dom/indexedDB/PIndexedDBPermissionRequest.ipdl
@@ -19,7 +19,7 @@ child:
    * @param permission
    *   The permission result (see nsIPermissionManager.idl for valid values).
    */
-  __delete__(uint32_t permission);
+  async __delete__(uint32_t permission);
 };
 
 } // namespace indexedDB
diff --git a/dom/ipc/PBlob.ipdl b/dom/ipc/PBlob.ipdl
index 09b78b16308..d2c04d3cdd1 100644
--- a/dom/ipc/PBlob.ipdl
+++ b/dom/ipc/PBlob.ipdl
@@ -26,12 +26,12 @@ sync protocol PBlob
   manages PBlobStream;
 
 both:
-  __delete__();
+  async __delete__();
 
 parent:
-  PBlobStream(uint64_t begin, uint64_t length);
+  async PBlobStream(uint64_t begin, uint64_t length);
 
-  ResolveMystery(ResolveMysteryParams params);
+  async ResolveMystery(ResolveMysteryParams params);
 
   sync BlobStreamSync(uint64_t begin, uint64_t length)
     returns (InputStreamParams params, OptionalFileDescriptorSet fds);
@@ -49,7 +49,7 @@ parent:
 child:
   // This method must be called by the parent when the PBlobParent is fully
   // created in order to release the known blob.
-  CreatedFromKnownBlob();
+  async CreatedFromKnownBlob();
 };
 
 } // namespace dom
diff --git a/dom/ipc/PBlobStream.ipdl b/dom/ipc/PBlobStream.ipdl
index 03f4f872925..c82304950ac 100644
--- a/dom/ipc/PBlobStream.ipdl
+++ b/dom/ipc/PBlobStream.ipdl
@@ -14,7 +14,7 @@ protocol PBlobStream
   manager PBlob;
 
 child:
-  __delete__(InputStreamParams params, OptionalFileDescriptorSet fds);
+  async __delete__(InputStreamParams params, OptionalFileDescriptorSet fds);
 };
 
 } // namespace dom
diff --git a/dom/ipc/PBrowser.ipdl b/dom/ipc/PBrowser.ipdl
index bd165838393..5563adb6962 100644
--- a/dom/ipc/PBrowser.ipdl
+++ b/dom/ipc/PBrowser.ipdl
@@ -110,14 +110,14 @@ prio(normal upto urgent) sync protocol PBrowser
     manages PPluginWidget;
 
 both:
-    AsyncMessage(nsString aMessage, ClonedMessageData aData, CpowEntry[] aCpows,
-                 Principal aPrincipal);
+    async AsyncMessage(nsString aMessage, ClonedMessageData aData, CpowEntry[] aCpows,
+                       Principal aPrincipal);
 
     /**
      * Create a layout frame (encapsulating a remote layer tree) for
      * the page that is currently loaded in the <browser>.
      */
-    PRenderFrame();
+    async PRenderFrame();
 
 parent:
     /**
@@ -126,7 +126,7 @@ parent:
      * aParentAcc is the id of the accessible in that document the new document
      * is a child of.
      */
-    PDocAccessible(nullable PDocAccessible aParentDoc, uint64_t aParentAcc);
+    async PDocAccessible(nullable PDocAccessible aParentDoc, uint64_t aParentAcc);
 
     /*
      * Creates a new remoted nsIWidget connection for windowed plugins
@@ -158,9 +158,9 @@ parent:
      * When child sends this message, parent should move focus to
      * the next or previous focusable element or document.
      */
-    MoveFocus(bool forward, bool forDocumentNavigation);
+    async MoveFocus(bool forward, bool forDocumentNavigation);
 
-    Event(RemoteDOMEvent aEvent);
+    async Event(RemoteDOMEvent aEvent);
 
     sync SyncMessage(nsString aMessage, ClonedMessageData aData,
                      CpowEntry[] aCpows, Principal aPrincipal)
@@ -295,15 +295,15 @@ parent:
      * Request that the parent process move focus to the browser's frame. If
      * canRaise is true, the window can be raised if it is inactive.
      */
-    RequestFocus(bool canRaise);
+    async RequestFocus(bool canRaise);
 
     /**
      * Indicate, based on the current state, that some commands are enabled and
      * some are disabled.
      */
-    EnableDisableCommands(nsString action,
-                          nsCString[] enabledCommands,
-                          nsCString[] disabledCommands);
+    async EnableDisableCommands(nsString action,
+                                nsCString[] enabledCommands,
+                                nsCString[] disabledCommands);
 
     prio(urgent) sync GetInputContext() returns (int32_t IMEEnabled,
                                                  int32_t IMEOpen);
@@ -341,7 +341,7 @@ parent:
      *   Invalidate any locally cached cursor settings and force an
      *   update.
      */
-    SetCursor(uint32_t value, bool force);
+    async SetCursor(uint32_t value, bool force);
 
     /**
      * Set the native cursor using a custom image.
@@ -363,30 +363,30 @@ parent:
      *   Invalidate any locally cached cursor settings and force an
      *   update.
      */
-    SetCustomCursor(nsCString cursorData, uint32_t width, uint32_t height,
-                    uint32_t stride, uint8_t format,
-                    uint32_t hotspotX, uint32_t hotspotY, bool force);
+    async SetCustomCursor(nsCString cursorData, uint32_t width, uint32_t height,
+                          uint32_t stride, uint8_t format,
+                          uint32_t hotspotX, uint32_t hotspotY, bool force);
 
     /**
      * Used to set the current text of the status tooltip.
      * Nowadays this is mainly used for link locations on hover.
      */
-    SetStatus(uint32_t type, nsString status);
+    async SetStatus(uint32_t type, nsString status);
 
     /**
      * Show/hide a tooltip when the mouse hovers over an element in the content
      * document.
      */
-    ShowTooltip(uint32_t x, uint32_t y, nsString tooltip);
-    HideTooltip();
+    async ShowTooltip(uint32_t x, uint32_t y, nsString tooltip);
+    async HideTooltip();
 
     /**
      * Create an asynchronous color picker on the parent side,
      * but don't open it yet.
      */
-    PColorPicker(nsString title, nsString initialColor);
+    async PColorPicker(nsString title, nsString initialColor);
 
-    PFilePicker(nsString aTitle, int16_t aMode);
+    async PFilePicker(nsString aTitle, int16_t aMode);
 
     /**
      * Initiates an asynchronous request for one of the special indexedDB
@@ -399,7 +399,7 @@ parent:
      *       principals that can live in the content process should
      *       provided.
      */
-    PIndexedDBPermissionRequest(Principal principal);
+    async PIndexedDBPermissionRequest(Principal principal);
 
     /**
      * window.open from inside <iframe mozbrowser> is special.  When the child
@@ -420,7 +420,7 @@ parent:
      * Instructs the TabParent to forward a request to zoom to a rect given in
      * CSS pixels. This rect is relative to the document.
      */
-    ZoomToRect(uint32_t aPresShellId, ViewID aViewId, CSSRect aRect, uint32_t aFlags);
+    async ZoomToRect(uint32_t aPresShellId, ViewID aViewId, CSSRect aRect, uint32_t aFlags);
 
     /**
      * We know for sure that content has either preventDefaulted or not
@@ -429,36 +429,36 @@ parent:
      * batched and only processed for panning and zooming if content does not
      * preventDefault.
      */
-    ContentReceivedInputBlock(ScrollableLayerGuid aGuid, uint64_t aInputBlockId, bool aPreventDefault);
+    async ContentReceivedInputBlock(ScrollableLayerGuid aGuid, uint64_t aInputBlockId, bool aPreventDefault);
 
     /**
      * Notifies the APZ code of the results of the gecko hit-test for a
      * particular input block. Each target corresponds to one touch point in the
      * touch event.
      */
-    SetTargetAPZC(uint64_t aInputBlockId, ScrollableLayerGuid[] aTargets);
+    async SetTargetAPZC(uint64_t aInputBlockId, ScrollableLayerGuid[] aTargets);
 
     /**
      * Notifies the APZ code of the allowed touch-behaviours for a particular
      * input block. Each item in the aFlags array corresponds to one touch point
      * in the touch event.
      */
-    SetAllowedTouchBehavior(uint64_t aInputBlockId, TouchBehaviorFlags[] aFlags);
+    async SetAllowedTouchBehavior(uint64_t aInputBlockId, TouchBehaviorFlags[] aFlags);
 
     /**
      * Updates the zoom constraints for a scrollable frame in this tab.
      * The zoom controller code lives on the parent side and so this allows it to
      * have up-to-date zoom constraints.
      */
-    UpdateZoomConstraints(uint32_t aPresShellId, ViewID aViewId,
-                          MaybeZoomConstraints aConstraints);
+    async UpdateZoomConstraints(uint32_t aPresShellId, ViewID aViewId,
+                                MaybeZoomConstraints aConstraints);
 
     /**
      * Tells the containing widget whether the given input block results in a
      * swipe. Should be called in response to a WidgetWheelEvent that has
      * mFlags.mCanTriggerSwipe set on it.
      */
-    RespondStartSwipeEvent(uint64_t aInputBlockId, bool aStartSwipe);
+    async RespondStartSwipeEvent(uint64_t aInputBlockId, bool aStartSwipe);
 
     /**
      * Brings up the auth prompt dialog.
@@ -467,49 +467,49 @@ parent:
      * root process.  It will be passed back to the root process with either the
      * OnAuthAvailable or OnAuthCancelled message.
      */
-    AsyncAuthPrompt(nsCString uri, nsString realm, uint64_t aCallbackId);
+    async AsyncAuthPrompt(nsCString uri, nsString realm, uint64_t aCallbackId);
 
-    __delete__();
+    async __delete__();
 
-    ReplyKeyEvent(WidgetKeyboardEvent event);
+    async ReplyKeyEvent(WidgetKeyboardEvent event);
 
-    DispatchAfterKeyboardEvent(WidgetKeyboardEvent event);
+    async DispatchAfterKeyboardEvent(WidgetKeyboardEvent event);
 
     sync RequestNativeKeyBindings(WidgetKeyboardEvent event)
         returns (MaybeNativeKeyBinding bindings);
 
-    SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
-                             int32_t aNativeKeyCode,
-                             uint32_t aModifierFlags,
-                             nsString aCharacters,
-                             nsString aUnmodifiedCharacters,
-                             uint64_t aObserverId);
-    SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
-                               uint32_t aNativeMessage,
-                               uint32_t aModifierFlags,
-                               uint64_t aObserverId);
-    SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
-                              uint64_t aObserverId);
-    SynthesizeNativeMouseScrollEvent(LayoutDeviceIntPoint aPoint,
+    async SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
+                                   int32_t aNativeKeyCode,
+                                   uint32_t aModifierFlags,
+                                   nsString aCharacters,
+                                   nsString aUnmodifiedCharacters,
+                                   uint64_t aObserverId);
+    async SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
                                      uint32_t aNativeMessage,
-                                     double aDeltaX,
-                                     double aDeltaY,
-                                     double aDeltaZ,
                                      uint32_t aModifierFlags,
-                                     uint32_t aAdditionalFlags,
                                      uint64_t aObserverId);
-    SynthesizeNativeTouchPoint(uint32_t aPointerId,
-                               TouchPointerState aPointerState,
-                               ScreenIntPoint aPointerScreenPoint,
-                               double aPointerPressure,
-                               uint32_t aPointerOrientation,
-                               uint64_t aObserverId);
-    SynthesizeNativeTouchTap(ScreenIntPoint aPointerScreenPoint,
-                             bool aLongTap,
-                             uint64_t aObserverId);
-    ClearNativeTouchSequence(uint64_t aObserverId);
+    async SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                    uint64_t aObserverId);
+    async SynthesizeNativeMouseScrollEvent(LayoutDeviceIntPoint aPoint,
+                                           uint32_t aNativeMessage,
+                                           double aDeltaX,
+                                           double aDeltaY,
+                                           double aDeltaZ,
+                                           uint32_t aModifierFlags,
+                                           uint32_t aAdditionalFlags,
+                                           uint64_t aObserverId);
+    async SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                     TouchPointerState aPointerState,
+                                     ScreenIntPoint aPointerScreenPoint,
+                                     double aPointerPressure,
+                                     uint32_t aPointerOrientation,
+                                     uint64_t aObserverId);
+    async SynthesizeNativeTouchTap(ScreenIntPoint aPointerScreenPoint,
+                                   bool aLongTap,
+                                   uint64_t aObserverId);
+    async ClearNativeTouchSequence(uint64_t aObserverId);
 child:
-    NativeSynthesisResponse(uint64_t aObserverId, nsCString aResponse);
+    async NativeSynthesisResponse(uint64_t aObserverId, nsCString aResponse);
 
 
 parent:
@@ -540,9 +540,10 @@ parent:
     // Start an APZ drag on a scrollbar
     async StartScrollbarDrag(AsyncDragMetrics aDragMetrics);
 
-    InvokeDragSession(IPCDataTransfer[] transfers, uint32_t action,
-                      nsCString visualData, uint32_t width, uint32_t height,
-                      uint32_t stride, uint8_t format, int32_t dragAreaX, int32_t dragAreaY);
+    async InvokeDragSession(IPCDataTransfer[] transfers, uint32_t action,
+                            nsCString visualData, uint32_t width, uint32_t height,
+                            uint32_t stride, uint8_t format,
+                            int32_t dragAreaX, int32_t dragAreaY);
 
     async AudioChannelActivityNotification(uint32_t aAudioChannel,
                                            bool aActive);
@@ -557,74 +558,74 @@ child:
      * content processes always render to a virtual <0, 0> top-left
      * point.
      */
-    Show(ScreenIntSize size,
-         ShowInfo info,
-         TextureFactoryIdentifier textureFactoryIdentifier,
-         uint64_t layersId,
-         nullable PRenderFrame renderFrame,
-         bool parentIsActive);
+    async Show(ScreenIntSize size,
+               ShowInfo info,
+               TextureFactoryIdentifier textureFactoryIdentifier,
+               uint64_t layersId,
+               nullable PRenderFrame renderFrame,
+               bool parentIsActive);
 
-    LoadURL(nsCString uri, BrowserConfiguration config, ShowInfo info);
+    async LoadURL(nsCString uri, BrowserConfiguration config, ShowInfo info);
 
-    OpenURI(URIParams uri, uint32_t flags);
+    async OpenURI(URIParams uri, uint32_t flags);
 
-    CacheFileDescriptor(nsString path, FileDescriptor fd);
+    async CacheFileDescriptor(nsString path, FileDescriptor fd);
 
-    UpdateDimensions(CSSRect rect, CSSSize size, nsSizeMode sizeMode,
-                     ScreenOrientationInternal orientation,
-                     LayoutDeviceIntPoint chromeDisp) compressall;
+    async UpdateDimensions(CSSRect rect, CSSSize size, nsSizeMode sizeMode,
+                           ScreenOrientationInternal orientation,
+                           LayoutDeviceIntPoint chromeDisp) compressall;
 
-    UpdateFrame(FrameMetrics frame);
+    async UpdateFrame(FrameMetrics frame);
 
     // The following methods correspond to functions on the GeckoContentController
     // interface in gfx/layers/apz/public/GeckoContentController.h. Refer to documentation
     // in that file for these functions.
-    RequestFlingSnap(ViewID aScrollID, CSSPoint aDestination);
-    AcknowledgeScrollUpdate(ViewID aScrollId, uint32_t aScrollGeneration);
-    HandleDoubleTap(CSSPoint aPoint, Modifiers aModifiers, ScrollableLayerGuid aGuid);
-    HandleSingleTap(CSSPoint aPoint, Modifiers aModifiers, ScrollableLayerGuid aGuid);
-    HandleLongTap(CSSPoint point, Modifiers aModifiers, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
-    NotifyAPZStateChange(ViewID aViewId, APZStateChange aChange, int aArg);
-    NotifyFlushComplete();
+    async RequestFlingSnap(ViewID aScrollID, CSSPoint aDestination);
+    async AcknowledgeScrollUpdate(ViewID aScrollId, uint32_t aScrollGeneration);
+    async HandleDoubleTap(CSSPoint aPoint, Modifiers aModifiers, ScrollableLayerGuid aGuid);
+    async HandleSingleTap(CSSPoint aPoint, Modifiers aModifiers, ScrollableLayerGuid aGuid);
+    async HandleLongTap(CSSPoint point, Modifiers aModifiers, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
+    async NotifyAPZStateChange(ViewID aViewId, APZStateChange aChange, int aArg);
+    async NotifyFlushComplete();
 
 
     /**
      * Sending an activate message moves focus to the child.
      */
-    Activate();
+    async Activate();
 
-    Deactivate();
+    async Deactivate();
 
-    ParentActivated(bool aActivated);
+    async ParentActivated(bool aActivated);
 
     /**
      * StopIMEStateManagement() is called when the process loses focus and
      * should stop managing IME state.
      */
-    StopIMEStateManagement();
+    async StopIMEStateManagement();
 
     /**
      * MenuKeyboardListenerInstalled() is called when menu keyboard listener
      * is installed in the parent process.
      */
-    MenuKeyboardListenerInstalled(bool aInstalled);
+    async MenuKeyboardListenerInstalled(bool aInstalled);
 
     /**
      * @see nsIDOMWindowUtils sendMouseEvent.
      */
-    MouseEvent(nsString aType,
-               float aX,
-               float aY,
-               int32_t aButton,
-               int32_t aClickCount,
-               int32_t aModifiers,
-               bool aIgnoreRootScrollFrame);
+    async MouseEvent(nsString aType,
+                     float aX,
+                     float aY,
+                     int32_t aButton,
+                     int32_t aClickCount,
+                     int32_t aModifiers,
+                     bool aIgnoreRootScrollFrame);
 
     /**
      * When two consecutive mouse move events would be added to the message queue,
      * they are 'compressed' by dumping the oldest one.
      */
-    RealMouseMoveEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId) compress;
+    async RealMouseMoveEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId) compress;
     /**
      * Mouse move events with |reason == eSynthesized| are sent via a separate
      * message because they do not generate DOM 'mousemove' events, and the
@@ -632,45 +633,45 @@ child:
      * |reason == eReal| event being dropped in favour of an |eSynthesized|
      * event, and thus a DOM 'mousemove' event to be lost.
      */
-    SynthMouseMoveEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
-    RealMouseButtonEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
-    RealKeyEvent(WidgetKeyboardEvent event, MaybeNativeKeyBinding keyBinding);
-    MouseWheelEvent(WidgetWheelEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
-    RealTouchEvent(WidgetTouchEvent aEvent,
-                   ScrollableLayerGuid aGuid,
-                   uint64_t aInputBlockId,
-                   nsEventStatus aApzResponse);
-    RealTouchMoveEvent(WidgetTouchEvent aEvent,
-                       ScrollableLayerGuid aGuid,
-                       uint64_t aInputBlockId,
-                       nsEventStatus aApzResponse);
-    RealDragEvent(WidgetDragEvent aEvent, uint32_t aDragAction, uint32_t aDropEffect);
-    PluginEvent(WidgetPluginEvent aEvent);
+    async SynthMouseMoveEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
+    async RealMouseButtonEvent(WidgetMouseEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
+    async RealKeyEvent(WidgetKeyboardEvent event, MaybeNativeKeyBinding keyBinding);
+    async MouseWheelEvent(WidgetWheelEvent event, ScrollableLayerGuid aGuid, uint64_t aInputBlockId);
+    async RealTouchEvent(WidgetTouchEvent aEvent,
+                         ScrollableLayerGuid aGuid,
+                         uint64_t aInputBlockId,
+                         nsEventStatus aApzResponse);
+    async RealTouchMoveEvent(WidgetTouchEvent aEvent,
+                             ScrollableLayerGuid aGuid,
+                             uint64_t aInputBlockId,
+                             nsEventStatus aApzResponse);
+    async RealDragEvent(WidgetDragEvent aEvent, uint32_t aDragAction, uint32_t aDropEffect);
+    async PluginEvent(WidgetPluginEvent aEvent);
 
     /**
      * @see nsIDOMWindowUtils sendKeyEvent.
      */
-    KeyEvent(nsString aType,
-             int32_t aKeyCode,
-             int32_t aCharCode,
-             int32_t aModifiers,
-             bool aPreventDefault);
+    async KeyEvent(nsString aType,
+                   int32_t aKeyCode,
+                   int32_t aCharCode,
+                   int32_t aModifiers,
+                   bool aPreventDefault);
 
     /**
      * APZ notification for mouse scroll testing events.
      */
-    MouseScrollTestEvent(ViewID aScrollId, nsString aEvent);
+    async MouseScrollTestEvent(ViewID aScrollId, nsString aEvent);
 
-    CompositionEvent(WidgetCompositionEvent event);
+    async CompositionEvent(WidgetCompositionEvent event);
 
-    SelectionEvent(WidgetSelectionEvent event);
+    async SelectionEvent(WidgetSelectionEvent event);
 
     /**
      * Activate event forwarding from client to parent.
      */
-    ActivateFrameEvent(nsString aType, bool capture);
+    async ActivateFrameEvent(nsString aType, bool capture);
 
-    LoadRemoteScript(nsString aURL, bool aRunInGlobalScope);
+    async LoadRemoteScript(nsString aURL, bool aRunInGlobalScope);
 
     /**
      * Create a asynchronous request to render whatever document is
@@ -685,10 +686,10 @@ child:
      * and if true, |flushLayout| will do just that before rendering
      * the document.  The rendered image will be of size |renderSize|.
      */
-    PDocumentRenderer(nsRect documentRect, Matrix transform,
-                      nsString bgcolor,
-                      uint32_t renderFlags, bool flushLayout,
-                      IntSize renderSize);
+    async PDocumentRenderer(nsRect documentRect, Matrix transform,
+                            nsString bgcolor,
+                            uint32_t renderFlags, bool flushLayout,
+                            IntSize renderSize);
 
     /**
      * Sent by the chrome process when it no longer wants this remote
@@ -696,19 +697,19 @@ child:
      * finalizing its death by sending back __delete__() to the
      * parent.
      */
-    Destroy();
+    async Destroy();
 
 
     /**
      * Tell the child side if it has to update it's touchable region
      * to the parent.
      */
-    SetUpdateHitRegion(bool aEnabled);
+    async SetUpdateHitRegion(bool aEnabled);
 
     /**
      * Update the child side docShell active (resource use) state.
      */
-    SetDocShellIsActive(bool aIsActive, bool aIsHidden);
+    async SetDocShellIsActive(bool aIsActive, bool aIsHidden);
 
     /**
      * Notify the child that it shouldn't paint the offscreen displayport.
@@ -724,7 +725,7 @@ child:
     /**
      * Navigate by key (Tab/Shift+Tab/F6/Shift+f6).
      */
-    NavigateByKey(bool aForward, bool aForDocumentNavigation);
+    async NavigateByKey(bool aForward, bool aForDocumentNavigation);
 
     /**
      * The parent (chrome thread) requests that the child inform it when
@@ -743,24 +744,24 @@ child:
      * value (-1) but in the majority of the cases this saves us from two
      * sync requests from the child to the parent.
      */
-    UIResolutionChanged(float dpi, double scale);
+    async UIResolutionChanged(float dpi, double scale);
 
     /**
      * Tell the child that the system theme has changed, and that a repaint
      * is necessary.
      */
-    ThemeChanged(LookAndFeelInt[] lookAndFeelIntCache);
+    async ThemeChanged(LookAndFeelInt[] lookAndFeelIntCache);
 
     /**
      * Tell the child of an app's offline status
      */
-    AppOfflineStatus(uint32_t id, bool offline);
+    async AppOfflineStatus(uint32_t id, bool offline);
 
     /**
      * Tell the browser that its frame loader has been swapped
      * with another.
      */
-    SwappedWithOtherRemoteLoader();
+    async SwappedWithOtherRemoteLoader();
 
     /**
      * A potential accesskey was just pressed. Look for accesskey targets
@@ -770,14 +771,14 @@ child:
      * @param isTrusted true if triggered by a trusted key event
      * @param modifierMask indicates which accesskey modifiers are pressed
      */
-    HandleAccessKey(uint32_t[] charCodes, bool isTrusted, int32_t modifierMask);
+    async HandleAccessKey(uint32_t[] charCodes, bool isTrusted, int32_t modifierMask);
 
     /**
      * Propagate a refresh to the child process
      */
-    AudioChannelChangeNotification(uint32_t aAudioChannel,
-                                   float aVolume,
-                                   bool aMuted);
+    async AudioChannelChangeNotification(uint32_t aAudioChannel,
+                                         float aVolume,
+                                         bool aMuted);
 
 /*
  * FIXME: write protocol!
diff --git a/dom/ipc/PColorPicker.ipdl b/dom/ipc/PColorPicker.ipdl
index 04990c88702..0e54ad598c7 100644
--- a/dom/ipc/PColorPicker.ipdl
+++ b/dom/ipc/PColorPicker.ipdl
@@ -15,12 +15,12 @@ protocol PColorPicker
     manager PBrowser;
 
 parent:
-    Open();
+    async Open();
 
 child:
-    Update(nsString color);
+    async Update(nsString color);
 
-    __delete__(nsString color);
+    async __delete__(nsString color);
 };
 
 } // namespace dom
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index e388993d384..626c4d7b47f 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -532,14 +532,14 @@ both:
 
     async PBlob(BlobConstructorParams params);
 
-    PFileDescriptorSet(FileDescriptor fd);
+    async PFileDescriptorSet(FileDescriptor fd);
 
     // For parent->child, aBrowser must be non-null; aOuterWindowID can
     // be 0 to indicate the browser's current root document, or nonzero
     // to persist a subdocument.  For child->parent, arguments are
     // ignored and should be null/zero.
-    PWebBrowserPersistDocument(nullable PBrowser aBrowser,
-                               uint64_t aOuterWindowID);
+    async PWebBrowserPersistDocument(nullable PBrowser aBrowser,
+                                     uint64_t aOuterWindowID);
 
 child:
     /**
@@ -549,8 +549,8 @@ child:
      */
     async SetProcessSandbox(MaybeFileDesc aBroker);
 
-    PMemoryReportRequest(uint32_t generation, bool anonymize,
-                         bool minimizeMemoryUsage, MaybeFileDesc DMDFile);
+    async PMemoryReportRequest(uint32_t generation, bool anonymize,
+                               bool minimizeMemoryUsage, MaybeFileDesc DMDFile);
 
     async SpeakerManagerNotify();
 
@@ -569,15 +569,15 @@ child:
      * For documentation on the other args, see dumpGCAndCCLogsToFile in
      * nsIMemoryInfoDumper.idl
      */
-    PCycleCollectWithLogs(bool dumpAllTraces,
-                          FileDescriptor gcLog,
-                          FileDescriptor ccLog);
+    async PCycleCollectWithLogs(bool dumpAllTraces,
+                                FileDescriptor gcLog,
+                                FileDescriptor ccLog);
 
-    PTestShell();
+    async PTestShell();
 
-    RegisterChrome(ChromePackage[] packages, SubstitutionMapping[] substitutions,
-                   OverrideMapping[] overrides, nsCString locale, bool reset);
-    RegisterChromeItem(ChromeRegistryItem item);
+    async RegisterChrome(ChromePackage[] packages, SubstitutionMapping[] substitutions,
+                         OverrideMapping[] overrides, nsCString locale, bool reset);
+    async RegisterChromeItem(ChromeRegistryItem item);
 
     async SetOffline(bool offline);
     async SetConnectivity(bool connectivity);
@@ -586,59 +586,59 @@ child:
 
     async SystemMemoryAvailable(uint64_t getterId, uint32_t memoryAvailable);
 
-    PreferenceUpdate(PrefSetting pref);
+    async PreferenceUpdate(PrefSetting pref);
 
-    DataStoragePut(nsString aFilename, DataStorageItem aItem);
-    DataStorageRemove(nsString aFilename, nsCString aKey, DataStorageType aType);
-    DataStorageClear(nsString aFilename);
+    async DataStoragePut(nsString aFilename, DataStorageItem aItem);
+    async DataStorageRemove(nsString aFilename, nsCString aKey, DataStorageType aType);
+    async DataStorageClear(nsString aFilename);
 
-    NotifyAlertsObserver(nsCString topic, nsString data);
+    async NotifyAlertsObserver(nsCString topic, nsString data);
 
-    GeolocationUpdate(GeoPosition somewhere);
+    async GeolocationUpdate(GeoPosition somewhere);
 
-    GeolocationError(uint16_t errorCode);
+    async GeolocationError(uint16_t errorCode);
 
-    UpdateDictionaryList(nsString[] dictionaries);
+    async UpdateDictionaryList(nsString[] dictionaries);
 
     // nsIPermissionManager messages
-    AddPermission(Permission permission);
+    async AddPermission(Permission permission);
 
-    ScreenSizeChanged(IntSize size);
+    async ScreenSizeChanged(IntSize size);
 
-    Volumes(VolumeInfo[] volumes);
+    async Volumes(VolumeInfo[] volumes);
 
-    FlushMemory(nsString reason);
+    async FlushMemory(nsString reason);
 
-    GarbageCollect();
-    CycleCollect();
+    async GarbageCollect();
+    async CycleCollect();
 
     /**
      * Start accessibility engine in content process.
      */
-    ActivateA11y();
+    async ActivateA11y();
 
-    AppInfo(nsCString version, nsCString buildID, nsCString name, nsCString UAName,
-            nsCString ID, nsCString vendor);
-    AppInit();
+    async AppInfo(nsCString version, nsCString buildID, nsCString name, nsCString UAName,
+                  nsCString ID, nsCString vendor);
+    async AppInit();
 
     // Notify child that last-pb-context-exited notification was observed
-    LastPrivateDocShellDestroyed();
+    async LastPrivateDocShellDestroyed();
 
-    FilePathUpdate(nsString storageType, nsString storageName, nsString filepath,
-                   nsCString reasons);
+    async FilePathUpdate(nsString storageType, nsString storageName, nsString filepath,
+                         nsCString reasons);
 
     // Note: Any changes to this structure should also be changed in
     // VolumeInfo above.
-    FileSystemUpdate(nsString fsName, nsString mountPoint, int32_t fsState,
-                     int32_t mountGeneration, bool isMediaPresent,
-                     bool isSharing, bool isFormatting, bool isFake,
-                     bool isUnmounting, bool isRemovable, bool isHotSwappable);
+    async FileSystemUpdate(nsString fsName, nsString mountPoint, int32_t fsState,
+                           int32_t mountGeneration, bool isMediaPresent,
+                           bool isSharing, bool isFormatting, bool isFake,
+                           bool isUnmounting, bool isRemovable, bool isHotSwappable);
 
     // Notify volume is removed.
-    VolumeRemoved(nsString fsName);
+    async VolumeRemoved(nsString fsName);
 
-    NotifyProcessPriorityChanged(ProcessPriority priority);
-    MinimizeMemoryUsage();
+    async NotifyProcessPriorityChanged(ProcessPriority priority);
+    async MinimizeMemoryUsage();
 
     /**
      * Used to manage nsIStyleSheetService across processes.
@@ -646,17 +646,17 @@ child:
     async LoadAndRegisterSheet(URIParams uri, uint32_t type);
     async UnregisterSheet(URIParams uri, uint32_t type);
 
-    NotifyPhoneStateChange(nsString newState);
+    async NotifyPhoneStateChange(nsString newState);
 
     /**
      * Notify idle observers in the child
      */
-    NotifyIdleObserver(uint64_t observerId, nsCString topic, nsString str);
+    async NotifyIdleObserver(uint64_t observerId, nsCString topic, nsString str);
 
     /**
      * Notify windows in the child to apply a new app style.
      */
-    OnAppThemeChanged();
+    async OnAppThemeChanged();
 
     /**
      * Called during plugin initialization to map a plugin id to a child process
@@ -680,9 +680,9 @@ child:
 
     async GatherProfile();
 
-    InvokeDragSession(IPCDataTransfer[] transfers, uint32_t action);
+    async InvokeDragSession(IPCDataTransfer[] transfers, uint32_t action);
 
-    EndDragSession(bool aDoneDrag, bool aUserCancelled);
+    async EndDragSession(bool aDoneDrag, bool aUserCancelled);
 
     async DomainSetChanged(uint32_t aSetType, uint32_t aChangeType, OptionalURIParams aDomain);
 
@@ -703,7 +703,7 @@ child:
     /**
      * Send gamepad status update to child.
      */
-    GamepadUpdate(GamepadChangeEvent aGamepadEvent);
+    async GamepadUpdate(GamepadChangeEvent aGamepadEvent);
 
     /**
      * Tell the child that for testing purposes, a graphics device reset has
@@ -731,17 +731,17 @@ child:
     /**
      * Send a `push` event without data to a service worker in the child.
      */
-    Push(nsCString scope, Principal principal);
+    async Push(nsCString scope, Principal principal);
 
     /**
      * Send a `push` event with data to a service worker in the child.
      */
-    PushWithData(nsCString scope, Principal principal, uint8_t[] data);
+    async PushWithData(nsCString scope, Principal principal, uint8_t[] data);
 
     /**
      * Send a `pushsubscriptionchange` event to a service worker in the child.
      */
-    PushSubscriptionChange(nsCString scope, Principal principal);
+    async PushSubscriptionChange(nsCString scope, Principal principal);
 
 parent:
     /**
@@ -814,10 +814,10 @@ parent:
 
     async PJavaScript();
 
-    PRemoteSpellcheckEngine();
-    PDeviceStorageRequest(DeviceStorageParams params);
+    async PRemoteSpellcheckEngine();
+    async PDeviceStorageRequest(DeviceStorageParams params);
 
-    PFileSystemRequest(FileSystemParams params);
+    async PFileSystemRequest(FileSystemParams params);
 
     sync PCrashReporter(NativeThreadId tid, uint32_t processType);
 
@@ -838,40 +838,40 @@ parent:
 
     async PHeapSnapshotTempFileHelper();
 
-    PIcc(uint32_t serviceId);
+    async PIcc(uint32_t serviceId);
 
-    PMobileConnection(uint32_t clientId);
+    async PMobileConnection(uint32_t clientId);
 
-    PNecko();
+    async PNecko();
 
-    PPrinting();
+    async PPrinting();
 
     prio(high) sync PScreenManager()
         returns (uint32_t numberOfScreens,
                  float systemDefaultScale,
                  bool success);
 
-    PCellBroadcast();
+    async PCellBroadcast();
 
-    PSms();
+    async PSms();
 
-    PSpeechSynthesis();
+    async PSpeechSynthesis();
 
     prio(urgent) async PStorage();
 
-    PTelephony();
+    async PTelephony();
 
-    PVoicemail();
+    async PVoicemail();
 
-    PMedia();
+    async PMedia();
 
-    PBluetooth();
+    async PBluetooth();
 
-    PFMRadio();
+    async PFMRadio();
 
-    PWebrtcGlobal();
+    async PWebrtcGlobal();
 
-    PPresentation();
+    async PPresentation();
 
     // Services remoting
 
@@ -897,44 +897,44 @@ parent:
                                CpowEntry[] aCpows, Principal aPrincipal)
       returns (StructuredCloneData[] retval);
 
-    ShowAlert(AlertNotificationType alert);
+    async ShowAlert(AlertNotificationType alert);
 
-    CloseAlert(nsString name, Principal principal);
+    async CloseAlert(nsString name, Principal principal);
 
-    DisableNotifications(Principal principal);
+    async DisableNotifications(Principal principal);
 
-    OpenNotificationSettings(Principal principal);
+    async OpenNotificationSettings(Principal principal);
 
-    PPSMContentDownloader(uint32_t aCertType);
+    async PPSMContentDownloader(uint32_t aCertType);
 
-    PExternalHelperApp(OptionalURIParams uri,
-                       nsCString aMimeContentType,
-                       nsCString aContentDisposition,
-                       uint32_t aContentDispositionHint,
-                       nsString aContentDispositionFilename,
-                       bool aForceSave,
-                       int64_t aContentLength,
-                       OptionalURIParams aReferrer,
-                       nullable PBrowser aBrowser);
+    async PExternalHelperApp(OptionalURIParams uri,
+                             nsCString aMimeContentType,
+                             nsCString aContentDisposition,
+                             uint32_t aContentDispositionHint,
+                             nsString aContentDispositionFilename,
+                             bool aForceSave,
+                             int64_t aContentLength,
+                             OptionalURIParams aReferrer,
+                             nullable PBrowser aBrowser);
 
-    PHandlerService();
+    async PHandlerService();
 
-    AddGeolocationListener(Principal principal, bool highAccuracy);
-    RemoveGeolocationListener();
-    SetGeolocationHigherAccuracy(bool enable);
+    async AddGeolocationListener(Principal principal, bool highAccuracy);
+    async RemoveGeolocationListener();
+    async SetGeolocationHigherAccuracy(bool enable);
 
-    ConsoleMessage(nsString message);
-    ScriptError(nsString message, nsString sourceName, nsString sourceLine,
-                uint32_t lineNumber, uint32_t colNumber, uint32_t flags,
-                nsCString category);
+    async ConsoleMessage(nsString message);
+    async ScriptError(nsString message, nsString sourceName, nsString sourceLine,
+                      uint32_t lineNumber, uint32_t colNumber, uint32_t flags,
+                      nsCString category);
 
     // nsIPermissionManager messages
     sync ReadPermissions() returns (Permission[] permissions);
 
     // Places the items within dataTransfer on the clipboard.
-    SetClipboard(IPCDataTransfer aDataTransfer,
-                 bool aIsPrivateData,
-                 int32_t aWhichClipboard);
+    async SetClipboard(IPCDataTransfer aDataTransfer,
+                       bool aIsPrivateData,
+                       int32_t aWhichClipboard);
 
     // Given a list of supported types, returns the clipboard data for the
     // first type that matches.
@@ -942,7 +942,7 @@ parent:
         returns (IPCDataTransfer dataTransfer);
 
     // Clears the clipboard.
-    EmptyClipboard(int32_t aWhichClipboard);
+    async EmptyClipboard(int32_t aWhichClipboard);
 
     // Returns true if data of one of the specified types is on the clipboard.
     sync ClipboardHasType(nsCString[] aTypes, int32_t aWhichClipboard)
@@ -958,7 +958,7 @@ parent:
         returns (bool showPassword);
 
     // Notify the parent of the presence or absence of private docshells
-    PrivateDocShellsExist(bool aExist);
+    async PrivateDocShellsExist(bool aExist);
 
     // Tell the parent that the child has gone idle for the first time
     async FirstIdle();
@@ -1020,8 +1020,8 @@ parent:
     sync BeginDriverCrashGuard(uint32_t aGuardType) returns (bool crashDetected);
     sync EndDriverCrashGuard(uint32_t aGuardType);
 
-    AddIdleObserver(uint64_t observerId, uint32_t idleTimeInS);
-    RemoveIdleObserver(uint64_t observerId, uint32_t idleTimeInS);
+    async AddIdleObserver(uint64_t observerId, uint32_t idleTimeInS);
+    async RemoveIdleObserver(uint64_t observerId, uint32_t idleTimeInS);
 
     /**
      * This message is only used on X11 platforms.
@@ -1034,7 +1034,7 @@ parent:
      * crashes *just before* a repaint and the parent process tries to
      * use the newly-invalid surface.
      */
-    BackUpXResources(FileDescriptor aXSocketFd);
+    async BackUpXResources(FileDescriptor aXSocketFd);
 
     sync OpenAnonymousTemporaryFile() returns (FileDescOrError aFD);
 
@@ -1056,7 +1056,7 @@ parent:
         returns (nsString aAttribute, nsString[] aContent);
 
     // Use only for testing!
-    FlushPendingFileDeletions();
+    async FlushPendingFileDeletions();
 
     /**
      * Tell the chrome process there is an creation of PBrowser.
@@ -1099,15 +1099,15 @@ parent:
      * @param tabId
      *   To identify which tab owns the app.
      */
-    POfflineCacheUpdate(URIParams manifestURI, URIParams documentURI,
-                        PrincipalInfo loadingPrincipal, bool stickDocument);
+    async POfflineCacheUpdate(URIParams manifestURI, URIParams documentURI,
+                              PrincipalInfo loadingPrincipal, bool stickDocument);
 
     /**
      * Sets "offline-app" permission for the principal.  Called when we hit
      * a web app with the manifest attribute in <html> and
      * offline-apps.allow_by_default is set to true.
      */
-    SetOfflinePermission(Principal principal);
+    async SetOfflinePermission(Principal principal);
 
     /**
      * Notifies the parent to continue shutting down after the child performs
@@ -1115,7 +1115,7 @@ parent:
      */
     async FinishShutdown();
 
-    UpdateDropEffect(uint32_t aDragAction, uint32_t aDropEffect);
+    async UpdateDropEffect(uint32_t aDragAction, uint32_t aDropEffect);
 
     /**
      * Initiates an asynchronous request for permission for the
@@ -1132,8 +1132,8 @@ parent:
      *       principals that can live in the content process should
      *       provided.
      */
-    PContentPermissionRequest(PermissionRequest[] aRequests, Principal aPrincipal,
-                              TabId tabId);
+    async PContentPermissionRequest(PermissionRequest[] aRequests, Principal aPrincipal,
+                                    TabId tabId);
 
     /**
      * Send ServiceWorkerRegistrationData to child process.
@@ -1144,12 +1144,12 @@ parent:
     /*
      * Tells the parent to start the gamepad listening service if it hasn't already.
      */
-    GamepadListenerAdded();
+    async GamepadListenerAdded();
 
     /**
      * Tells the parent to stop the gamepad listening service if it hasn't already.
      */
-    GamepadListenerRemoved();
+    async GamepadListenerRemoved();
 
     async Profile(nsCString aProfile);
 
@@ -1191,8 +1191,8 @@ parent:
      */
     sync UngrabPointer(uint32_t time);
 both:
-     AsyncMessage(nsString aMessage, ClonedMessageData aData,
-                  CpowEntry[] aCpows, Principal aPrincipal);
+     async AsyncMessage(nsString aMessage, ClonedMessageData aData,
+                        CpowEntry[] aCpows, Principal aPrincipal);
 };
 
 }
diff --git a/dom/ipc/PContentBridge.ipdl b/dom/ipc/PContentBridge.ipdl
index 982e5adefbc..5295f9c037e 100644
--- a/dom/ipc/PContentBridge.ipdl
+++ b/dom/ipc/PContentBridge.ipdl
@@ -51,8 +51,8 @@ both:
 
     async PBlob(BlobConstructorParams params);
 
-    AsyncMessage(nsString aMessage, ClonedMessageData aData,
-                 CpowEntry[] aCpows, Principal aPrincipal);
+    async AsyncMessage(nsString aMessage, ClonedMessageData aData,
+                       CpowEntry[] aCpows, Principal aPrincipal);
 };
 
 }
diff --git a/dom/ipc/PContentDialog.ipdl b/dom/ipc/PContentDialog.ipdl
index 10d4dfe716c..2eee67315ca 100644
--- a/dom/ipc/PContentDialog.ipdl
+++ b/dom/ipc/PContentDialog.ipdl
@@ -15,7 +15,7 @@ protocol PContentDialog
   manager PBrowser;
 
 child:
-    __delete__(int32_t[] aIntParams, nsString[] aStringParams);
+    async __delete__(int32_t[] aIntParams, nsString[] aStringParams);
 };
 
 } // namespace dom
diff --git a/dom/ipc/PContentPermissionRequest.ipdl b/dom/ipc/PContentPermissionRequest.ipdl
index 0afe7092843..8eb827862f0 100644
--- a/dom/ipc/PContentPermissionRequest.ipdl
+++ b/dom/ipc/PContentPermissionRequest.ipdl
@@ -13,14 +13,14 @@ protocol PContentPermissionRequest
   manager PContent;
 
 parent:
-  prompt();
-  NotifyVisibility(bool visibility);
-  Destroy();
+  async prompt();
+  async NotifyVisibility(bool visibility);
+  async Destroy();
 
 child:
-  GetVisibility();
-  NotifyResult(bool allow, PermissionChoice[] choices);
-  __delete__();
+  async GetVisibility();
+  async NotifyResult(bool allow, PermissionChoice[] choices);
+  async __delete__();
 };
 
 
diff --git a/dom/ipc/PCrashReporter.ipdl b/dom/ipc/PCrashReporter.ipdl
index 41cfd356b7c..8f965f2eec0 100644
--- a/dom/ipc/PCrashReporter.ipdl
+++ b/dom/ipc/PCrashReporter.ipdl
@@ -22,9 +22,9 @@ struct Mapping {
 async protocol PCrashReporter {
   manager PContent or PPluginModule or PGMP;
 parent:
-  AnnotateCrashReport(nsCString key, nsCString data);
-  AppendAppNotes(nsCString data);
-  __delete__();
+  async AnnotateCrashReport(nsCString key, nsCString data);
+  async AppendAppNotes(nsCString data);
+  async __delete__();
 };
 
 }
diff --git a/dom/ipc/PCycleCollectWithLogs.ipdl b/dom/ipc/PCycleCollectWithLogs.ipdl
index c1fb560b19d..f420c6ddae5 100644
--- a/dom/ipc/PCycleCollectWithLogs.ipdl
+++ b/dom/ipc/PCycleCollectWithLogs.ipdl
@@ -12,10 +12,10 @@ protocol PCycleCollectWithLogs {
     manager PContent;
 
 parent:
-    CloseGCLog();
-    CloseCCLog();
+    async CloseGCLog();
+    async CloseCCLog();
 
-    __delete__();
+    async __delete__();
 };
 
 }
diff --git a/dom/ipc/PDocumentRenderer.ipdl b/dom/ipc/PDocumentRenderer.ipdl
index be3053d0147..bdaed45d741 100644
--- a/dom/ipc/PDocumentRenderer.ipdl
+++ b/dom/ipc/PDocumentRenderer.ipdl
@@ -18,7 +18,7 @@ protocol PDocumentRenderer
 
 parent:
     // Returns the width and height, in pixels, of the returned ARGB32 data.
-    __delete__(nsIntSize renderedSize, nsCString data);
+    async __delete__(nsIntSize renderedSize, nsCString data);
 };
 
 } // namespace ipc
diff --git a/dom/ipc/PFilePicker.ipdl b/dom/ipc/PFilePicker.ipdl
index 2eb1f2a85d1..aff58b011da 100644
--- a/dom/ipc/PFilePicker.ipdl
+++ b/dom/ipc/PFilePicker.ipdl
@@ -28,12 +28,12 @@ protocol PFilePicker
   manager PBrowser;
 
 parent:
-    Open(int16_t selectedType, bool addToRecentDocs, nsString defaultFile,
-         nsString defaultExtension, nsString[] filters, nsString[] filterNames,
-         nsString displayDirectory);
+    async Open(int16_t selectedType, bool addToRecentDocs, nsString defaultFile,
+               nsString defaultExtension, nsString[] filters, nsString[] filterNames,
+               nsString displayDirectory);
 
 child:
-    __delete__(MaybeInputFiles files, int16_t result);
+    async __delete__(MaybeInputFiles files, int16_t result);
 };
 
 } // namespace dom
diff --git a/dom/ipc/PMemoryReportRequest.ipdl b/dom/ipc/PMemoryReportRequest.ipdl
index f1aaa4413e7..092d4425096 100644
--- a/dom/ipc/PMemoryReportRequest.ipdl
+++ b/dom/ipc/PMemoryReportRequest.ipdl
@@ -21,8 +21,8 @@ protocol PMemoryReportRequest {
   manager PContent;
 
 parent:
-  Report(MemoryReport aReport);
-  __delete__();
+  async Report(MemoryReport aReport);
+  async __delete__();
 };
 
 }
diff --git a/dom/ipc/PScreenManager.ipdl b/dom/ipc/PScreenManager.ipdl
index 844821c8f44..77d036b910f 100644
--- a/dom/ipc/PScreenManager.ipdl
+++ b/dom/ipc/PScreenManager.ipdl
@@ -55,7 +55,7 @@ parent:
                bool success);
 
 child:
-    __delete__();
+    async __delete__();
 };
 
 } // namespace dom
diff --git a/dom/media/gmp/PGMPAudioDecoder.ipdl b/dom/media/gmp/PGMPAudioDecoder.ipdl
index 0c23145efe4..9af9415c82c 100644
--- a/dom/media/gmp/PGMPAudioDecoder.ipdl
+++ b/dom/media/gmp/PGMPAudioDecoder.ipdl
@@ -18,18 +18,18 @@ async protocol PGMPAudioDecoder
 {
   manager PGMPContent;
 child:
-  InitDecode(GMPAudioCodecData aCodecSettings);
-  Decode(GMPAudioEncodedSampleData aInput);
-  Reset();
-  Drain();
-  DecodingComplete();
+  async InitDecode(GMPAudioCodecData aCodecSettings);
+  async Decode(GMPAudioEncodedSampleData aInput);
+  async Reset();
+  async Drain();
+  async DecodingComplete();
 parent:
-  __delete__();
-  Decoded(GMPAudioDecodedSampleData aDecoded);
-  InputDataExhausted();
-  DrainComplete();
-  ResetComplete();
-  Error(GMPErr aErr);
+  async __delete__();
+  async Decoded(GMPAudioDecodedSampleData aDecoded);
+  async InputDataExhausted();
+  async DrainComplete();
+  async ResetComplete();
+  async Error(GMPErr aErr);
   async Shutdown();
 };
 
diff --git a/dom/media/gmp/PGMPDecryptor.ipdl b/dom/media/gmp/PGMPDecryptor.ipdl
index 0ec39b2030d..994004c8c5a 100644
--- a/dom/media/gmp/PGMPDecryptor.ipdl
+++ b/dom/media/gmp/PGMPDecryptor.ipdl
@@ -20,70 +20,70 @@ async protocol PGMPDecryptor
   manager PGMPContent;
 child:
 
-  Init();
+  async Init();
 
-  CreateSession(uint32_t aCreateSessionToken,
-                uint32_t aPromiseId,
-                nsCString aInitDataType,
-                uint8_t[] aInitData,
-                GMPSessionType aSessionType);
+  async CreateSession(uint32_t aCreateSessionToken,
+                      uint32_t aPromiseId,
+                      nsCString aInitDataType,
+                      uint8_t[] aInitData,
+                      GMPSessionType aSessionType);
 
-  LoadSession(uint32_t aPromiseId,
-              nsCString aSessionId);
+  async LoadSession(uint32_t aPromiseId,
+                    nsCString aSessionId);
 
-  UpdateSession(uint32_t aPromiseId,
-                nsCString aSessionId,
-                uint8_t[] aResponse);
+  async UpdateSession(uint32_t aPromiseId,
+                      nsCString aSessionId,
+                      uint8_t[] aResponse);
 
-  CloseSession(uint32_t aPromiseId,
-               nsCString aSessionId);
+  async CloseSession(uint32_t aPromiseId,
+                     nsCString aSessionId);
 
-  RemoveSession(uint32_t aPromiseId,
-                nsCString aSessionId);
+  async RemoveSession(uint32_t aPromiseId,
+                      nsCString aSessionId);
 
-  SetServerCertificate(uint32_t aPromiseId,
-                       uint8_t[] aServerCert);
+  async SetServerCertificate(uint32_t aPromiseId,
+                             uint8_t[] aServerCert);
 
-  Decrypt(uint32_t aId,
-          uint8_t[] aBuffer,
-          GMPDecryptionData aMetadata);
+  async Decrypt(uint32_t aId,
+                uint8_t[] aBuffer,
+                GMPDecryptionData aMetadata);
 
-  DecryptingComplete();
+  async DecryptingComplete();
 
 parent:
-  __delete__();
+  async __delete__();
 
-  SetSessionId(uint32_t aCreateSessionToken,
-               nsCString aSessionId);
+  async SetSessionId(uint32_t aCreateSessionToken,
+                     nsCString aSessionId);
 
-  ResolveLoadSessionPromise(uint32_t aPromiseId,
-                            bool aSuccess);
+  async ResolveLoadSessionPromise(uint32_t aPromiseId,
+                                  bool aSuccess);
 
-  ResolvePromise(uint32_t aPromiseId);
+  async ResolvePromise(uint32_t aPromiseId);
 
-  RejectPromise(uint32_t aPromiseId,
-                GMPDOMException aDOMExceptionCode,
-                nsCString aMessage);
+  async RejectPromise(uint32_t aPromiseId,
+                      GMPDOMException aDOMExceptionCode,
+                      nsCString aMessage);
 
-  SessionMessage(nsCString aSessionId,
-                 GMPSessionMessageType aMessageType,
-                 uint8_t[] aMessage);
+  async SessionMessage(nsCString aSessionId,
+                       GMPSessionMessageType aMessageType,
+                       uint8_t[] aMessage);
 
-  ExpirationChange(nsCString aSessionId, double aExpiryTime);
+  async ExpirationChange(nsCString aSessionId, double aExpiryTime);
 
-  SessionClosed(nsCString aSessionId);
+  async SessionClosed(nsCString aSessionId);
 
-  SessionError(nsCString aSessionId,
-               GMPDOMException aDOMExceptionCode,
-               uint32_t aSystemCode,
-               nsCString aMessage);
+  async SessionError(nsCString aSessionId,
+                     GMPDOMException aDOMExceptionCode,
+                     uint32_t aSystemCode,
+                     nsCString aMessage);
 
-  KeyStatusChanged(nsCString aSessionId, uint8_t[] aKey,
-                   GMPMediaKeyStatus aStatus);
+  async KeyStatusChanged(nsCString aSessionId, uint8_t[] aKey,
+                         GMPMediaKeyStatus aStatus);
 
-  SetCaps(uint64_t aCaps);
+  async SetCaps(uint64_t aCaps);
 
-  Decrypted(uint32_t aId, GMPErr aResult, uint8_t[] aBuffer);
+  async Decrypted(uint32_t aId, GMPErr aResult, uint8_t[] aBuffer);
 
   async Shutdown();
 };
diff --git a/dom/media/gmp/PGMPStorage.ipdl b/dom/media/gmp/PGMPStorage.ipdl
index 1ebdd985346..4d858312ae6 100644
--- a/dom/media/gmp/PGMPStorage.ipdl
+++ b/dom/media/gmp/PGMPStorage.ipdl
@@ -16,19 +16,19 @@ async protocol PGMPStorage
   manager PGMP;
 
 child:
-  OpenComplete(nsCString aRecordName, GMPErr aStatus);
-  ReadComplete(nsCString aRecordName, GMPErr aStatus, uint8_t[] aBytes);
-  WriteComplete(nsCString aRecordName, GMPErr aStatus);
-  RecordNames(nsCString[] aRecordNames, GMPErr aStatus);
-  Shutdown();
+  async OpenComplete(nsCString aRecordName, GMPErr aStatus);
+  async ReadComplete(nsCString aRecordName, GMPErr aStatus, uint8_t[] aBytes);
+  async WriteComplete(nsCString aRecordName, GMPErr aStatus);
+  async RecordNames(nsCString[] aRecordNames, GMPErr aStatus);
+  async Shutdown();
 
 parent:
-  Open(nsCString aRecordName);
-  Read(nsCString aRecordName);
-  Write(nsCString aRecordName, uint8_t[] aBytes);
-  Close(nsCString aRecordName);
-  GetRecordNames();
-  __delete__();
+  async Open(nsCString aRecordName);
+  async Read(nsCString aRecordName);
+  async Write(nsCString aRecordName, uint8_t[] aBytes);
+  async Close(nsCString aRecordName);
+  async GetRecordNames();
+  async __delete__();
 
 };
 
diff --git a/dom/media/gmp/PGMPTimer.ipdl b/dom/media/gmp/PGMPTimer.ipdl
index 57bea28f2c0..7a486bc3aaf 100644
--- a/dom/media/gmp/PGMPTimer.ipdl
+++ b/dom/media/gmp/PGMPTimer.ipdl
@@ -12,10 +12,10 @@ async protocol PGMPTimer
 {
   manager PGMP;
 child:
-  TimerExpired(uint32_t aTimerId);
+  async TimerExpired(uint32_t aTimerId);
 parent:
-  SetTimer(uint32_t aTimerId, uint32_t aTimeoutMs);
-  __delete__();
+  async SetTimer(uint32_t aTimerId, uint32_t aTimeoutMs);
+  async __delete__();
 };
 
 } // namespace gmp
diff --git a/dom/media/systemservices/PMedia.ipdl b/dom/media/systemservices/PMedia.ipdl
index e56e246d136..c060f030eb4 100644
--- a/dom/media/systemservices/PMedia.ipdl
+++ b/dom/media/systemservices/PMedia.ipdl
@@ -28,8 +28,8 @@ parent:
    * from a secondary pool that is never persisted to disk, and aPersist is
    * ignored.
    */
-  GetOriginKey(uint32_t aRequestId, nsCString aOrigin, bool aPrivateBrowsing,
-               bool aPersist);
+  async GetOriginKey(uint32_t aRequestId, nsCString aOrigin, bool aPrivateBrowsing,
+                     bool aPersist);
 
   /**
    * Clear per-orgin list of persistent deviceIds stored for enumerateDevices
@@ -40,11 +40,11 @@ parent:
    * aOnlyPrivateBrowsing - if true then only purge the separate in-memory
    *                        per-origin list used in Private Browsing.
    */
-  SanitizeOriginKeys(uint64_t aSinceWhen, bool aOnlyPrivateBrowsing);
+  async SanitizeOriginKeys(uint64_t aSinceWhen, bool aOnlyPrivateBrowsing);
 
 child:
-  GetOriginKeyResponse(uint32_t aRequestId, nsCString key);
-  __delete__();
+  async GetOriginKeyResponse(uint32_t aRequestId, nsCString key);
+  async __delete__();
 };
 
 } // namespace media
diff --git a/dom/media/webrtc/PWebrtcGlobal.ipdl b/dom/media/webrtc/PWebrtcGlobal.ipdl
index b3dd4a35465..4516347544a 100644
--- a/dom/media/webrtc/PWebrtcGlobal.ipdl
+++ b/dom/media/webrtc/PWebrtcGlobal.ipdl
@@ -16,17 +16,17 @@ async protocol PWebrtcGlobal {
   manager PContent;
 
 child: // parent -> child messages
-  GetStatsRequest(int aRequestId, nsString aPcIdFilter);
-  ClearStatsRequest();
-  GetLogRequest(int aRequestId, nsCString aPattern);
-  ClearLogRequest();
-  SetAecLogging(bool aEnable);
-  SetDebugMode(int aLevel);
+  async GetStatsRequest(int aRequestId, nsString aPcIdFilter);
+  async ClearStatsRequest();
+  async GetLogRequest(int aRequestId, nsCString aPattern);
+  async ClearLogRequest();
+  async SetAecLogging(bool aEnable);
+  async SetDebugMode(int aLevel);
 
 parent: // child -> parent messages
-  GetStatsResult(int aRequestId, RTCStatsReportInternal[] aStats);
-  GetLogResult(int aRequestId, WebrtcGlobalLog aLog);
-  __delete__();
+  async GetStatsResult(int aRequestId, RTCStatsReportInternal[] aStats);
+  async GetLogResult(int aRequestId, WebrtcGlobalLog aLog);
+  async __delete__();
 };
 
 } // end namespace net
diff --git a/dom/media/webspeech/synth/ipc/PSpeechSynthesis.ipdl b/dom/media/webspeech/synth/ipc/PSpeechSynthesis.ipdl
index 0b4f506119b..c9f8554606e 100644
--- a/dom/media/webspeech/synth/ipc/PSpeechSynthesis.ipdl
+++ b/dom/media/webspeech/synth/ipc/PSpeechSynthesis.ipdl
@@ -25,19 +25,19 @@ sync protocol PSpeechSynthesis
 
 child:
 
-    VoiceAdded(RemoteVoice aVoice);
+    async VoiceAdded(RemoteVoice aVoice);
 
-    VoiceRemoved(nsString aUri);
+    async VoiceRemoved(nsString aUri);
 
-    SetDefaultVoice(nsString aUri, bool aIsDefault);
+    async SetDefaultVoice(nsString aUri, bool aIsDefault);
 
-    IsSpeakingChanged(bool aIsSpeaking);
+    async IsSpeakingChanged(bool aIsSpeaking);
 
 parent:
-    __delete__();
+    async __delete__();
 
-    PSpeechSynthesisRequest(nsString aText, nsString aUri, nsString aLang,
-                            float aVolume, float aRate, float aPitch);
+    async PSpeechSynthesisRequest(nsString aText, nsString aUri, nsString aLang,
+                                  float aVolume, float aRate, float aPitch);
 
     sync ReadVoicesAndState() returns (RemoteVoice[] aVoices,
                                        nsString[] aDefaults, bool aIsSpeaking);
diff --git a/dom/media/webspeech/synth/ipc/PSpeechSynthesisRequest.ipdl b/dom/media/webspeech/synth/ipc/PSpeechSynthesisRequest.ipdl
index db02f04868f..9ffea29f5b3 100644
--- a/dom/media/webspeech/synth/ipc/PSpeechSynthesisRequest.ipdl
+++ b/dom/media/webspeech/synth/ipc/PSpeechSynthesisRequest.ipdl
@@ -15,31 +15,31 @@ async protocol PSpeechSynthesisRequest
 
  parent:
 
-  __delete__();
+  async __delete__();
 
-  Pause();
+  async Pause();
 
-  Resume();
+  async Resume();
 
-  Cancel();
+  async Cancel();
 
-  ForceEnd();
+  async ForceEnd();
 
-  SetAudioOutputVolume(float aVolume);
+  async SetAudioOutputVolume(float aVolume);
 
  child:
 
-  OnEnd(bool aIsError, float aElapsedTime, uint32_t aCharIndex);
+  async OnEnd(bool aIsError, float aElapsedTime, uint32_t aCharIndex);
 
-  OnStart(nsString aUri);
+  async OnStart(nsString aUri);
 
-  OnPause(float aElapsedTime, uint32_t aCharIndex);
+  async OnPause(float aElapsedTime, uint32_t aCharIndex);
 
-  OnResume(float aElapsedTime, uint32_t aCharIndex);
+  async OnResume(float aElapsedTime, uint32_t aCharIndex);
 
-  OnBoundary(nsString aName, float aElapsedTime, uint32_t aCharIndex);
+  async OnBoundary(nsString aName, float aElapsedTime, uint32_t aCharIndex);
 
-  OnMark(nsString aName, float aElapsedTime, uint32_t aCharIndex);
+  async OnMark(nsString aName, float aElapsedTime, uint32_t aCharIndex);
 };
 
 } // namespace dom
diff --git a/dom/messagechannel/PMessagePort.ipdl b/dom/messagechannel/PMessagePort.ipdl
index 299b00fedf1..a838c685fe7 100644
--- a/dom/messagechannel/PMessagePort.ipdl
+++ b/dom/messagechannel/PMessagePort.ipdl
@@ -44,17 +44,17 @@ protocol PMessagePort
      4. Recv__delete__(); */
 
 parent:
-  PostMessages(MessagePortMessage[] messages);
-  Disentangle(MessagePortMessage[] messages);
-  StopSendingData();
-  Close();
+  async PostMessages(MessagePortMessage[] messages);
+  async Disentangle(MessagePortMessage[] messages);
+  async StopSendingData();
+  async Close();
 
 child:
-  Entangled(MessagePortMessage[] messages);
-  ReceiveData(MessagePortMessage[] messages);
-  StopSendingDataConfirmed();
+  async Entangled(MessagePortMessage[] messages);
+  async ReceiveData(MessagePortMessage[] messages);
+  async StopSendingDataConfirmed();
 
-  __delete__();
+  async __delete__();
 };
 
 } // namespace dom
diff --git a/dom/mobileconnection/ipc/PMobileConnection.ipdl b/dom/mobileconnection/ipc/PMobileConnection.ipdl
index ceaa9ad371c..5be76a0834e 100644
--- a/dom/mobileconnection/ipc/PMobileConnection.ipdl
+++ b/dom/mobileconnection/ipc/PMobileConnection.ipdl
@@ -18,29 +18,29 @@ sync protocol PMobileConnection
   manages PMobileConnectionRequest;
 
 child:
-  NotifyVoiceInfoChanged(nsMobileConnectionInfo aInfo);
-  NotifyDataInfoChanged(nsMobileConnectionInfo aInfo);
-  NotifyDataError(nsString aMessage);
-  NotifyCFStateChanged(uint16_t aAction, uint16_t aReason, nsString aNumber,
-                       uint16_t aTimeSeconds, uint16_t aServiceClass);
-  NotifyEmergencyCbModeChanged(bool aActive, uint32_t aTimeoutMs);
-  NotifyOtaStatusChanged(nsString aStatus);
-  NotifyRadioStateChanged(int32_t aRadioState);
-  NotifyClirModeChanged(uint32_t aMode);
-  NotifyLastNetworkChanged(nsString aNetwork);
-  NotifyLastHomeNetworkChanged(nsString aNetwork);
-  NotifyNetworkSelectionModeChanged(int32_t aMode);
+  async NotifyVoiceInfoChanged(nsMobileConnectionInfo aInfo);
+  async NotifyDataInfoChanged(nsMobileConnectionInfo aInfo);
+  async NotifyDataError(nsString aMessage);
+  async NotifyCFStateChanged(uint16_t aAction, uint16_t aReason, nsString aNumber,
+                             uint16_t aTimeSeconds, uint16_t aServiceClass);
+  async NotifyEmergencyCbModeChanged(bool aActive, uint32_t aTimeoutMs);
+  async NotifyOtaStatusChanged(nsString aStatus);
+  async NotifyRadioStateChanged(int32_t aRadioState);
+  async NotifyClirModeChanged(uint32_t aMode);
+  async NotifyLastNetworkChanged(nsString aNetwork);
+  async NotifyLastHomeNetworkChanged(nsString aNetwork);
+  async NotifyNetworkSelectionModeChanged(int32_t aMode);
 
 parent:
   /**
    * Send when child no longer needs to use PMobileConnection.
    */
-  __delete__();
+  async __delete__();
 
   /**
    * Sent when the child makes an asynchronous request to the parent.
    */
-  PMobileConnectionRequest(MobileConnectionRequest aRequest);
+  async PMobileConnectionRequest(MobileConnectionRequest aRequest);
 
   /**
    * Sync call only be called once per child actor for initialization.
diff --git a/dom/mobileconnection/ipc/PMobileConnectionRequest.ipdl b/dom/mobileconnection/ipc/PMobileConnectionRequest.ipdl
index 73c0be9c997..d2c8bdc05ca 100644
--- a/dom/mobileconnection/ipc/PMobileConnectionRequest.ipdl
+++ b/dom/mobileconnection/ipc/PMobileConnectionRequest.ipdl
@@ -19,7 +19,7 @@ child:
   /**
    * Send when asynchronous request has completed.
    */
-  __delete__(MobileConnectionReply aResponse);
+  async __delete__(MobileConnectionReply aResponse);
 };
 
 /**
diff --git a/dom/mobilemessage/ipc/PMobileMessageCursor.ipdl b/dom/mobilemessage/ipc/PMobileMessageCursor.ipdl
index cc82fb34e64..c2141204c00 100644
--- a/dom/mobilemessage/ipc/PMobileMessageCursor.ipdl
+++ b/dom/mobilemessage/ipc/PMobileMessageCursor.ipdl
@@ -17,15 +17,15 @@ protocol PMobileMessageCursor
   manager PSms;
 
 child:
-  NotifyResult(MobileMessageCursorData aData);
+  async NotifyResult(MobileMessageCursorData aData);
 
   /**
    * Sent when the asynchronous cursor request has completed.
    */
-  __delete__(int32_t aError);
+  async __delete__(int32_t aError);
 
 parent:
-  Continue();
+  async Continue();
 };
 
 } // namespace mobilemessage
diff --git a/dom/mobilemessage/ipc/PSms.ipdl b/dom/mobilemessage/ipc/PSms.ipdl
index fc9a41b0a6b..d402e1872a1 100644
--- a/dom/mobilemessage/ipc/PSms.ipdl
+++ b/dom/mobilemessage/ipc/PSms.ipdl
@@ -111,46 +111,46 @@ sync protocol PSms {
     manages PMobileMessageCursor;
 
 child:
-  NotifyReceivedMessage(MobileMessageData aMessageData);
+  async NotifyReceivedMessage(MobileMessageData aMessageData);
 
-  NotifyRetrievingMessage(MobileMessageData aMessageData);
+  async NotifyRetrievingMessage(MobileMessageData aMessageData);
 
-  NotifySendingMessage(MobileMessageData aMessageData);
+  async NotifySendingMessage(MobileMessageData aMessageData);
 
-  NotifySentMessage(MobileMessageData aMessageData);
+  async NotifySentMessage(MobileMessageData aMessageData);
 
-  NotifyFailedMessage(MobileMessageData aMessageData);
+  async NotifyFailedMessage(MobileMessageData aMessageData);
 
-  NotifyDeliverySuccessMessage(MobileMessageData aMessageData);
+  async NotifyDeliverySuccessMessage(MobileMessageData aMessageData);
 
-  NotifyDeliveryErrorMessage(MobileMessageData aMessageData);
+  async NotifyDeliveryErrorMessage(MobileMessageData aMessageData);
 
-  NotifyReceivedSilentMessage(MobileMessageData aMessageData);
+  async NotifyReceivedSilentMessage(MobileMessageData aMessageData);
 
-  NotifyReadSuccessMessage(MobileMessageData aMessageData);
+  async NotifyReadSuccessMessage(MobileMessageData aMessageData);
 
-  NotifyReadErrorMessage(MobileMessageData aMessageData);
+  async NotifyReadErrorMessage(MobileMessageData aMessageData);
 
-  NotifyDeletedMessageInfo(DeletedMessageInfoData aDeletedInfo);
+  async NotifyDeletedMessageInfo(DeletedMessageInfoData aDeletedInfo);
 
 parent:
   /**
    * Sent when the child no longer needs to use sms.
    */
-  __delete__();
+  async __delete__();
 
   /**
    * Sent when the child makes an asynchronous request to the parent.
    */
-  PSmsRequest(IPCSmsRequest request);
+  async PSmsRequest(IPCSmsRequest request);
 
   /**
    * Sent when the child makes an asynchronous cursor to the parent.
    */
-  PMobileMessageCursor(IPCMobileMessageCursor request);
+  async PMobileMessageCursor(IPCMobileMessageCursor request);
 
-  AddSilentNumber(nsString aNumber);
-  RemoveSilentNumber(nsString aNumber);
+  async AddSilentNumber(nsString aNumber);
+  async RemoveSilentNumber(nsString aNumber);
 };
 
 } // namespace mobilemessage
diff --git a/dom/mobilemessage/ipc/PSmsRequest.ipdl b/dom/mobilemessage/ipc/PSmsRequest.ipdl
index 381ee4b432e..72b611a010d 100644
--- a/dom/mobilemessage/ipc/PSmsRequest.ipdl
+++ b/dom/mobilemessage/ipc/PSmsRequest.ipdl
@@ -22,7 +22,7 @@ child:
   /**
    * Sent when the asynchronous request has completed.
    */
-  __delete__(MessageReply response);
+  async __delete__(MessageReply response);
 };
 
 struct ReplyMessageSend
diff --git a/dom/network/PTCPServerSocket.ipdl b/dom/network/PTCPServerSocket.ipdl
index 70503bcc407..fc92f014671 100644
--- a/dom/network/PTCPServerSocket.ipdl
+++ b/dom/network/PTCPServerSocket.ipdl
@@ -19,12 +19,12 @@ protocol PTCPServerSocket
   manager PNecko;
 
 parent:
-  Close();
-  RequestDelete();
+  async Close();
+  async RequestDelete();
 
 child:
-  CallbackAccept(PTCPSocket socket);
-  __delete__();
+  async CallbackAccept(PTCPSocket socket);
+  async __delete__();
 };
 
 } // namespace net
diff --git a/dom/network/PTCPSocket.ipdl b/dom/network/PTCPSocket.ipdl
index ced62c895cd..76193ddd23b 100644
--- a/dom/network/PTCPSocket.ipdl
+++ b/dom/network/PTCPSocket.ipdl
@@ -39,42 +39,42 @@ parent:
   // Forward calling to child's open() method to parent, expect TCPOptions
   // is expanded to |useSSL| (from TCPOptions.useSecureTransport) and
   // |binaryType| (from TCPOption.binaryType).
-  Open(nsString host, uint16_t port, bool useSSL, bool useArrayBuffers);
+  async Open(nsString host, uint16_t port, bool useSSL, bool useArrayBuffers);
 
   // Ask parent to open a socket and bind the newly-opened socket to a local
   // address specified in |localAddr| and |localPort|.
-  OpenBind(nsCString host, uint16_t port,
-           nsCString localAddr, uint16_t localPort,
-           bool useSSL, bool aUseArrayBuffers);
+  async OpenBind(nsCString host, uint16_t port,
+                 nsCString localAddr, uint16_t localPort,
+                 bool useSSL, bool aUseArrayBuffers);
 
   // When child's send() is called, this message requrests parent to send
   // data and update it's trackingNumber.
-  Data(SendableData data, uint32_t trackingNumber);
+  async Data(SendableData data, uint32_t trackingNumber);
 
   // Forward calling to child's upgradeToSecure() method to parent.
-  StartTLS();
+  async StartTLS();
 
   // Forward calling to child's send() method to parent.
-  Suspend();
+  async Suspend();
 
   // Forward calling to child's resume() method to parent.
-  Resume();
+  async Resume();
 
   // Forward calling to child's close() method to parent.
-  Close();
+  async Close();
 
 child:
   // Forward events that are dispatched by parent.
-  Callback(nsString type, CallbackData data, uint32_t readyState);
+  async Callback(nsString type, CallbackData data, uint32_t readyState);
 
   // Update child's bufferedAmount when parent's bufferedAmount is updated.
   // trackingNumber is also passed back to child to ensure the bufferedAmount
   // is corresponding the last call to send().
-  UpdateBufferedAmount(uint32_t bufferedAmount, uint32_t trackingNumber);
+  async UpdateBufferedAmount(uint32_t bufferedAmount, uint32_t trackingNumber);
 
 both:
-  RequestDelete();
-  __delete__();
+  async RequestDelete();
+  async __delete__();
 };
 
 
diff --git a/dom/network/PUDPSocket.ipdl b/dom/network/PUDPSocket.ipdl
index c187ee366ac..0ead8b6ecd1 100644
--- a/dom/network/PUDPSocket.ipdl
+++ b/dom/network/PUDPSocket.ipdl
@@ -41,25 +41,25 @@ protocol PUDPSocket
   manager PNecko or PBackground;
 
 parent:
-  Bind(UDPAddressInfo addressInfo, bool addressReuse, bool loopback);
-  Connect(UDPAddressInfo addressInfo);
+  async Bind(UDPAddressInfo addressInfo, bool addressReuse, bool loopback);
+  async Connect(UDPAddressInfo addressInfo);
 
-  OutgoingData(UDPData data, UDPSocketAddr addr);
+  async OutgoingData(UDPData data, UDPSocketAddr addr);
 
-  JoinMulticast(nsCString multicastAddress, nsCString iface);
-  LeaveMulticast(nsCString multicastAddress, nsCString iface);
+  async JoinMulticast(nsCString multicastAddress, nsCString iface);
+  async LeaveMulticast(nsCString multicastAddress, nsCString iface);
 
-  Close();
+  async Close();
 
-  RequestDelete();
+  async RequestDelete();
 
 child:
-  CallbackOpened(UDPAddressInfo addressInfo);
-  CallbackConnected(UDPAddressInfo addressInfo);
-  CallbackClosed();
-  CallbackReceivedData(UDPAddressInfo addressInfo, uint8_t[] data);
-  CallbackError(nsCString message, nsCString filename, uint32_t lineNumber);
-  __delete__();
+  async CallbackOpened(UDPAddressInfo addressInfo);
+  async CallbackConnected(UDPAddressInfo addressInfo);
+  async CallbackClosed();
+  async CallbackReceivedData(UDPAddressInfo addressInfo, uint8_t[] data);
+  async CallbackError(nsCString message, nsCString filename, uint32_t lineNumber);
+  async __delete__();
 };
 
 
diff --git a/dom/plugins/ipc/PPluginBackgroundDestroyer.ipdl b/dom/plugins/ipc/PPluginBackgroundDestroyer.ipdl
index cbab923235e..cc8ff558e0d 100644
--- a/dom/plugins/ipc/PPluginBackgroundDestroyer.ipdl
+++ b/dom/plugins/ipc/PPluginBackgroundDestroyer.ipdl
@@ -27,7 +27,7 @@ protocol PPluginBackgroundDestroyer {
     // notification that that the background is stale.
 
 parent:
-    __delete__();
+    async __delete__();
 
 state DESTROYING:
     recv __delete__;
diff --git a/dom/presentation/ipc/PPresentation.ipdl b/dom/presentation/ipc/PPresentation.ipdl
index 9644e418a03..c027c54fbdc 100644
--- a/dom/presentation/ipc/PPresentation.ipdl
+++ b/dom/presentation/ipc/PPresentation.ipdl
@@ -50,26 +50,26 @@ sync protocol PPresentation
   manages PPresentationRequest;
 
 child:
-  NotifyAvailableChange(bool aAvailable);
-  NotifySessionStateChange(nsString aSessionId, uint16_t aState);
-  NotifyMessage(nsString aSessionId, nsCString aData);
-  NotifySessionConnect(uint64_t aWindowId, nsString aSessionId);
+  async NotifyAvailableChange(bool aAvailable);
+  async NotifySessionStateChange(nsString aSessionId, uint16_t aState);
+  async NotifyMessage(nsString aSessionId, nsCString aData);
+  async NotifySessionConnect(uint64_t aWindowId, nsString aSessionId);
 
 parent:
-  __delete__();
+  async __delete__();
 
-  RegisterAvailabilityHandler();
-  UnregisterAvailabilityHandler();
+  async RegisterAvailabilityHandler();
+  async UnregisterAvailabilityHandler();
 
-  RegisterSessionHandler(nsString aSessionId);
-  UnregisterSessionHandler(nsString aSessionId);
+  async RegisterSessionHandler(nsString aSessionId);
+  async UnregisterSessionHandler(nsString aSessionId);
 
-  RegisterRespondingHandler(uint64_t aWindowId);
-  UnregisterRespondingHandler(uint64_t aWindowId);
+  async RegisterRespondingHandler(uint64_t aWindowId);
+  async UnregisterRespondingHandler(uint64_t aWindowId);
 
-  PPresentationRequest(PresentationIPCRequest aRequest);
+  async PPresentationRequest(PresentationIPCRequest aRequest);
 
-  NotifyReceiverReady(nsString aSessionId);
+  async NotifyReceiverReady(nsString aSessionId);
 };
 
 } // namespace dom
diff --git a/dom/presentation/ipc/PPresentationRequest.ipdl b/dom/presentation/ipc/PPresentationRequest.ipdl
index 573e6bae8df..9680f9db011 100644
--- a/dom/presentation/ipc/PPresentationRequest.ipdl
+++ b/dom/presentation/ipc/PPresentationRequest.ipdl
@@ -14,7 +14,7 @@ sync protocol PPresentationRequest
   manager PPresentation;
 
 child:
-  __delete__(nsresult result);
+  async __delete__(nsresult result);
 };
 
 } // namespace dom
diff --git a/dom/quota/PQuota.ipdl b/dom/quota/PQuota.ipdl
index de24adc900e..d7e2e46b332 100644
--- a/dom/quota/PQuota.ipdl
+++ b/dom/quota/PQuota.ipdl
@@ -64,15 +64,15 @@ protocol PQuota
   manages PQuotaUsageRequest;
 
 parent:
-  __delete__();
+  async __delete__();
 
-  PQuotaUsageRequest(UsageRequestParams params);
+  async PQuotaUsageRequest(UsageRequestParams params);
 
-  PQuotaRequest(RequestParams params);
+  async PQuotaRequest(RequestParams params);
 
-  StartIdleMaintenance();
+  async StartIdleMaintenance();
 
-  StopIdleMaintenance();
+  async StopIdleMaintenance();
 };
 
 } // namespace quota
diff --git a/dom/quota/PQuotaRequest.ipdl b/dom/quota/PQuotaRequest.ipdl
index 82776eb1444..e42254e2aab 100644
--- a/dom/quota/PQuotaRequest.ipdl
+++ b/dom/quota/PQuotaRequest.ipdl
@@ -38,7 +38,7 @@ protocol PQuotaRequest
   manager PQuota;
 
 child:
-  __delete__(RequestResponse response);
+  async __delete__(RequestResponse response);
 };
 
 } // namespace quota
diff --git a/dom/quota/PQuotaUsageRequest.ipdl b/dom/quota/PQuotaUsageRequest.ipdl
index 530f65e328c..a132e0d0dac 100644
--- a/dom/quota/PQuotaUsageRequest.ipdl
+++ b/dom/quota/PQuotaUsageRequest.ipdl
@@ -25,10 +25,10 @@ protocol PQuotaUsageRequest
   manager PQuota;
 
 parent:
-  Cancel();
+  async Cancel();
 
 child:
-  __delete__(UsageRequestResponse response);
+  async __delete__(UsageRequestResponse response);
 };
 
 } // namespace quota
diff --git a/dom/telephony/ipc/PTelephony.ipdl b/dom/telephony/ipc/PTelephony.ipdl
index 57f559df1a0..9660d1dd1b9 100644
--- a/dom/telephony/ipc/PTelephony.ipdl
+++ b/dom/telephony/ipc/PTelephony.ipdl
@@ -125,43 +125,43 @@ sync protocol PTelephony {
   manages PTelephonyRequest;
 
 child:
-  NotifyCallStateChanged(nsTelephonyCallInfo[] aAllInfo);
+  async NotifyCallStateChanged(nsTelephonyCallInfo[] aAllInfo);
 
-  NotifyCdmaCallWaiting(uint32_t aClientId, IPCCdmaWaitingCallData aData);
+  async NotifyCdmaCallWaiting(uint32_t aClientId, IPCCdmaWaitingCallData aData);
 
-  NotifyConferenceError(nsString aName, nsString aMessage);
+  async NotifyConferenceError(nsString aName, nsString aMessage);
 
-  NotifySupplementaryService(uint32_t aClientId, int32_t aCallIndex,
-                             uint16_t aNotification);
+  async NotifySupplementaryService(uint32_t aClientId, int32_t aCallIndex,
+                                   uint16_t aNotification);
 
 parent:
   /**
    * Sent when the child no longer needs to use PTelephony.
    */
-  __delete__();
+  async __delete__();
 
   /**
    * Sent when the child makes an asynchronous request to the parent.
    */
-  PTelephonyRequest(IPCTelephonyRequest request);
+  async PTelephonyRequest(IPCTelephonyRequest request);
 
-  RegisterListener();
+  async RegisterListener();
 
-  UnregisterListener();
+  async UnregisterListener();
 
-  StartTone(uint32_t aClientId, nsString aTone);
+  async StartTone(uint32_t aClientId, nsString aTone);
 
-  StopTone(uint32_t aClientId);
+  async StopTone(uint32_t aClientId);
 
   sync GetMicrophoneMuted()
     returns (bool aMuted);
 
-  SetMicrophoneMuted(bool aMuted);
+  async SetMicrophoneMuted(bool aMuted);
 
   sync GetSpeakerEnabled()
     returns (bool aEnabled);
 
-  SetSpeakerEnabled(bool aEnabled);
+  async SetSpeakerEnabled(bool aEnabled);
 };
 
 } /* namespace telephony */
diff --git a/dom/telephony/ipc/PTelephonyRequest.ipdl b/dom/telephony/ipc/PTelephonyRequest.ipdl
index 0e4c86a3666..7a9755851ee 100644
--- a/dom/telephony/ipc/PTelephonyRequest.ipdl
+++ b/dom/telephony/ipc/PTelephonyRequest.ipdl
@@ -66,14 +66,14 @@ protocol PTelephonyRequest
   manager PTelephony;
 
 child:
-  NotifyEnumerateCallState(nsTelephonyCallInfo aInfo);
+  async NotifyEnumerateCallState(nsTelephonyCallInfo aInfo);
 
-  NotifyDialMMI(nsString aServiceCode);
+  async NotifyDialMMI(nsString aServiceCode);
 
   /**
    * Sent when the asynchronous request has completed.
    */
-  __delete__(IPCTelephonyResponse aResponse);
+  async __delete__(IPCTelephonyResponse aResponse);
 };
 
 } /* namespace telephony */
diff --git a/dom/voicemail/ipc/PVoicemail.ipdl b/dom/voicemail/ipc/PVoicemail.ipdl
index e612d95133e..5f37884cc90 100644
--- a/dom/voicemail/ipc/PVoicemail.ipdl
+++ b/dom/voicemail/ipc/PVoicemail.ipdl
@@ -15,21 +15,21 @@ sync protocol PVoicemail
   manager PContent;
 
 child:
-  NotifyInfoChanged(uint32_t aServiceId,
-                    nsString aNumber,
-                    nsString aDisplayName);
+  async NotifyInfoChanged(uint32_t aServiceId,
+                          nsString aNumber,
+                          nsString aDisplayName);
 
-  NotifyStatusChanged(uint32_t aServiceId,
-                      bool aHasMessages,
-                      int32_t aMessageCount,
-                      nsString aNumber,
-                      nsString aDisplayName);
+  async NotifyStatusChanged(uint32_t aServiceId,
+                            bool aHasMessages,
+                            int32_t aMessageCount,
+                            nsString aNumber,
+                            nsString aDisplayName);
 
 parent:
   /**
    * Send when child no longer needs to use PVoicemail.
    */
-  __delete__();
+  async __delete__();
 
   sync GetAttributes(uint32_t aServiceId)
     returns (nsString aNumber,
diff --git a/dom/workers/PServiceWorkerManager.ipdl b/dom/workers/PServiceWorkerManager.ipdl
index d77e7f2e826..e7b97672d00 100644
--- a/dom/workers/PServiceWorkerManager.ipdl
+++ b/dom/workers/PServiceWorkerManager.ipdl
@@ -17,28 +17,28 @@ protocol PServiceWorkerManager
   manager PBackground;
 
 parent:
-  Register(ServiceWorkerRegistrationData data);
+  async Register(ServiceWorkerRegistrationData data);
 
-  Unregister(PrincipalInfo principalInfo, nsString scope);
+  async Unregister(PrincipalInfo principalInfo, nsString scope);
 
-  PropagateSoftUpdate(PrincipalOriginAttributes originAttributes,
-                      nsString scope);
-  PropagateUnregister(PrincipalInfo principalInfo, nsString scope);
+  async PropagateSoftUpdate(PrincipalOriginAttributes originAttributes,
+                            nsString scope);
+  async PropagateUnregister(PrincipalInfo principalInfo, nsString scope);
 
-  PropagateRemove(nsCString host);
+  async PropagateRemove(nsCString host);
 
-  PropagateRemoveAll();
+  async PropagateRemoveAll();
 
-  Shutdown();
+  async Shutdown();
 
 child:
-  NotifyRegister(ServiceWorkerRegistrationData data);
-  NotifySoftUpdate(PrincipalOriginAttributes originAttributes, nsString scope);
-  NotifyUnregister(PrincipalInfo principalInfo, nsString scope);
-  NotifyRemove(nsCString host);
-  NotifyRemoveAll();
+  async NotifyRegister(ServiceWorkerRegistrationData data);
+  async NotifySoftUpdate(PrincipalOriginAttributes originAttributes, nsString scope);
+  async NotifyUnregister(PrincipalInfo principalInfo, nsString scope);
+  async NotifyRemove(nsCString host);
+  async NotifyRemoveAll();
 
-  __delete__();
+  async __delete__();
 };
 
 } // namespace dom
diff --git a/embedding/components/printingui/ipc/PPrintProgressDialog.ipdl b/embedding/components/printingui/ipc/PPrintProgressDialog.ipdl
index 3011f9a63b5..1da29ef87c9 100644
--- a/embedding/components/printingui/ipc/PPrintProgressDialog.ipdl
+++ b/embedding/components/printingui/ipc/PPrintProgressDialog.ipdl
@@ -13,22 +13,22 @@ protocol PPrintProgressDialog
   manager PPrinting;
 
 parent:
-  StateChange(long stateFlags,
-              nsresult status);
+  async StateChange(long stateFlags,
+                    nsresult status);
 
-  ProgressChange(long curSelfProgress,
-                 long maxSelfProgress,
-                 long curTotalProgress,
-                 long maxTotalProgress);
+  async ProgressChange(long curSelfProgress,
+                       long maxSelfProgress,
+                       long curTotalProgress,
+                       long maxTotalProgress);
 
-  DocTitleChange(nsString newTitle);
+  async DocTitleChange(nsString newTitle);
 
-  DocURLChange(nsString newURL);
+  async DocURLChange(nsString newURL);
 
-  __delete__();
+  async __delete__();
 
 child:
-  DialogOpened();
+  async DialogOpened();
 };
 
 } // namespace embedding
diff --git a/embedding/components/printingui/ipc/PPrintSettingsDialog.ipdl b/embedding/components/printingui/ipc/PPrintSettingsDialog.ipdl
index 95868e3e44d..3e436892ed0 100644
--- a/embedding/components/printingui/ipc/PPrintSettingsDialog.ipdl
+++ b/embedding/components/printingui/ipc/PPrintSettingsDialog.ipdl
@@ -22,7 +22,7 @@ protocol PPrintSettingsDialog
   manager PPrinting;
 
 child:
-  __delete__(PrintDataOrNSResult result);
+  async __delete__(PrintDataOrNSResult result);
 };
 
 } // namespace embedding
diff --git a/embedding/components/printingui/ipc/PPrinting.ipdl b/embedding/components/printingui/ipc/PPrinting.ipdl
index 1aee5787048..491c3815a0c 100644
--- a/embedding/components/printingui/ipc/PPrinting.ipdl
+++ b/embedding/components/printingui/ipc/PPrinting.ipdl
@@ -31,8 +31,8 @@ parent:
                         PBrowser browser,
                         PrintData settings);
 
-  PPrintProgressDialog();
-  PPrintSettingsDialog();
+  async PPrintProgressDialog();
+  async PPrintSettingsDialog();
 
   sync SavePrintSettings(PrintData settings, bool usePrinterNamePrefix,
                          uint32_t flags)
@@ -40,7 +40,7 @@ parent:
 
 child:
   async PRemotePrintJob();
-  __delete__();
+  async __delete__();
 };
 
 } // namespace embedding
diff --git a/embedding/components/webbrowserpersist/PWebBrowserPersistDocument.ipdl b/embedding/components/webbrowserpersist/PWebBrowserPersistDocument.ipdl
index ffcbf35aecb..143af0ebd95 100644
--- a/embedding/components/webbrowserpersist/PWebBrowserPersistDocument.ipdl
+++ b/embedding/components/webbrowserpersist/PWebBrowserPersistDocument.ipdl
@@ -59,19 +59,19 @@ parent:
   // two messages; see also the state transition rules.  The message
   // is either a response to the constructor (if it was parent->child)
   // or sent after it (if it was child->parent).
-  Attributes(WebBrowserPersistDocumentAttrs aAttrs,
-             OptionalInputStreamParams postData,
-             FileDescriptor[] postFiles);
-  InitFailure(nsresult aStatus);
+  async Attributes(WebBrowserPersistDocumentAttrs aAttrs,
+                   OptionalInputStreamParams postData,
+                   FileDescriptor[] postFiles);
+  async InitFailure(nsresult aStatus);
 
 child:
-  SetPersistFlags(uint32_t aNewFlags);
-  PWebBrowserPersistResources();
-  PWebBrowserPersistSerialize(WebBrowserPersistURIMap aMap,
-                              nsCString aRequestedContentType,
-                              uint32_t aEncoderFlags,
-                              uint32_t aWrapColumn);
-  __delete__();
+  async SetPersistFlags(uint32_t aNewFlags);
+  async PWebBrowserPersistResources();
+  async PWebBrowserPersistSerialize(WebBrowserPersistURIMap aMap,
+                                    nsCString aRequestedContentType,
+                                    uint32_t aEncoderFlags,
+                                    uint32_t aWrapColumn);
+  async __delete__();
 
 state START:
   recv Attributes goto MAIN;
diff --git a/embedding/components/webbrowserpersist/PWebBrowserPersistResources.ipdl b/embedding/components/webbrowserpersist/PWebBrowserPersistResources.ipdl
index 14798609ea9..3c36ae4954c 100644
--- a/embedding/components/webbrowserpersist/PWebBrowserPersistResources.ipdl
+++ b/embedding/components/webbrowserpersist/PWebBrowserPersistResources.ipdl
@@ -12,15 +12,15 @@ protocol PWebBrowserPersistResources {
   manager PWebBrowserPersistDocument;
 
 parent:
-  VisitResource(nsCString aURI);
+  async VisitResource(nsCString aURI);
 
   // The actor sent here is in the START state; the parent-side
   // receiver will have to wait for it to enter the MAIN state
   // before exposing it with a visitDocument call.
-  VisitDocument(PWebBrowserPersistDocument aSubDocument);
+  async VisitDocument(PWebBrowserPersistDocument aSubDocument);
 
   // This reflects the endVisit method.
-  __delete__(nsresult aStatus);
+  async __delete__(nsresult aStatus);
 };
 
 } // namespace mozilla
diff --git a/embedding/components/webbrowserpersist/PWebBrowserPersistSerialize.ipdl b/embedding/components/webbrowserpersist/PWebBrowserPersistSerialize.ipdl
index 02cd22de3e6..ff09fd3887f 100644
--- a/embedding/components/webbrowserpersist/PWebBrowserPersistSerialize.ipdl
+++ b/embedding/components/webbrowserpersist/PWebBrowserPersistSerialize.ipdl
@@ -19,11 +19,11 @@ parent:
   // this is at worst just a constant-factor increase in memory usage.
   // Also, Chromium does the same thing; see
   // content::RenderViewImpl::didSerializeDataForFrame.
-  WriteData(uint8_t[] aData);
+  async WriteData(uint8_t[] aData);
 
   // This is the onFinish method.
-  __delete__(nsCString aContentType,
-             nsresult aStatus);
+  async __delete__(nsCString aContentType,
+                   nsresult aStatus);
 };
 
 } // namespace mozilla
diff --git a/extensions/spellcheck/hunspell/glue/PRemoteSpellcheckEngine.ipdl b/extensions/spellcheck/hunspell/glue/PRemoteSpellcheckEngine.ipdl
index 6c724475e47..7fd91836446 100644
--- a/extensions/spellcheck/hunspell/glue/PRemoteSpellcheckEngine.ipdl
+++ b/extensions/spellcheck/hunspell/glue/PRemoteSpellcheckEngine.ipdl
@@ -10,7 +10,7 @@ sync protocol PRemoteSpellcheckEngine {
   manager PContent;
 
 parent:
-  __delete__();
+  async __delete__();
 
   sync Check(nsString aWord) returns (bool aIsMisspelled);
 
diff --git a/hal/sandbox/PHal.ipdl b/hal/sandbox/PHal.ipdl
index f22448f08e7..d2594dde88f 100644
--- a/hal/sandbox/PHal.ipdl
+++ b/hal/sandbox/PHal.ipdl
@@ -100,83 +100,83 @@ prio(normal upto urgent) sync protocol PHal {
     manager PContent;
 
 child:
-    NotifyBatteryChange(BatteryInformation aBatteryInfo);
-    NotifyNetworkChange(NetworkInformation aNetworkInfo);
-    NotifyWakeLockChange(WakeLockInformation aWakeLockInfo);
-    NotifyScreenConfigurationChange(ScreenConfiguration aScreenOrientation);
-    NotifySwitchChange(SwitchEvent aEvent);
-    NotifySystemClockChange(int64_t aClockDeltaMS); 
-    NotifySystemTimezoneChange(SystemTimezoneChangeInformation aSystemTimezoneChangeInfo); 
+    async NotifyBatteryChange(BatteryInformation aBatteryInfo);
+    async NotifyNetworkChange(NetworkInformation aNetworkInfo);
+    async NotifyWakeLockChange(WakeLockInformation aWakeLockInfo);
+    async NotifyScreenConfigurationChange(ScreenConfiguration aScreenOrientation);
+    async NotifySwitchChange(SwitchEvent aEvent);
+    async NotifySystemClockChange(int64_t aClockDeltaMS); 
+    async NotifySystemTimezoneChange(SystemTimezoneChangeInformation aSystemTimezoneChangeInfo); 
 
 parent:
-    Vibrate(uint32_t[] pattern, uint64_t[] id, PBrowser browser);
-    CancelVibrate(uint64_t[] id, PBrowser browser);
+    async Vibrate(uint32_t[] pattern, uint64_t[] id, PBrowser browser);
+    async CancelVibrate(uint64_t[] id, PBrowser browser);
 
-    EnableBatteryNotifications();
-    DisableBatteryNotifications();
+    async EnableBatteryNotifications();
+    async DisableBatteryNotifications();
     sync GetCurrentBatteryInformation()
       returns (BatteryInformation aBatteryInfo);
 
-    EnableNetworkNotifications();
-    DisableNetworkNotifications();
+    async EnableNetworkNotifications();
+    async DisableNetworkNotifications();
     sync GetCurrentNetworkInformation()
       returns (NetworkInformation aNetworkInfo);
 
     sync GetScreenEnabled() returns (bool enabled);
-    SetScreenEnabled(bool aEnabled);
+    async SetScreenEnabled(bool aEnabled);
 
     sync GetKeyLightEnabled() returns (bool enabled);
-    SetKeyLightEnabled(bool aEnabled);
+    async SetKeyLightEnabled(bool aEnabled);
 
     sync GetCpuSleepAllowed() returns (bool allowed);
-    SetCpuSleepAllowed(bool aAllowed);
+    async SetCpuSleepAllowed(bool aAllowed);
 
     sync GetScreenBrightness() returns (double brightness);
-    SetScreenBrightness(double aBrightness);
+    async SetScreenBrightness(double aBrightness);
 
-    AdjustSystemClock(int64_t aDeltaMilliseconds);
-    SetTimezone(nsCString aTimezoneSpec);
+    async AdjustSystemClock(int64_t aDeltaMilliseconds);
+    async SetTimezone(nsCString aTimezoneSpec);
     sync GetTimezone()
       returns (nsCString aTimezoneSpec);
     sync GetTimezoneOffset()
       returns (int32_t aTimezoneOffset);
-    EnableSystemClockChangeNotifications();
-    DisableSystemClockChangeNotifications();
-    EnableSystemTimezoneChangeNotifications();
-    DisableSystemTimezoneChangeNotifications();
+    async EnableSystemClockChangeNotifications();
+    async DisableSystemClockChangeNotifications();
+    async EnableSystemTimezoneChangeNotifications();
+    async DisableSystemTimezoneChangeNotifications();
 
-    ModifyWakeLock(nsString aTopic,
-                   WakeLockControl aLockAdjust,
-                   WakeLockControl aHiddenAdjust,
-                   uint64_t aProcessID);
-    EnableWakeLockNotifications();
-    DisableWakeLockNotifications();
+    async ModifyWakeLock(nsString aTopic,
+                         WakeLockControl aLockAdjust,
+                         WakeLockControl aHiddenAdjust,
+                         uint64_t aProcessID);
+    async EnableWakeLockNotifications();
+    async DisableWakeLockNotifications();
     sync GetWakeLockInfo(nsString aTopic)
       returns (WakeLockInformation aWakeLockInfo);
 
-    EnableScreenConfigurationNotifications();
-    DisableScreenConfigurationNotifications();
+    async EnableScreenConfigurationNotifications();
+    async DisableScreenConfigurationNotifications();
     prio(urgent) sync GetCurrentScreenConfiguration()
       returns (ScreenConfiguration aScreenConfiguration);
     sync LockScreenOrientation(ScreenOrientationInternal aOrientation)
       returns (bool allowed);
-    UnlockScreenOrientation();
+    async UnlockScreenOrientation();
  
-    EnableSwitchNotifications(SwitchDevice aDevice);
-    DisableSwitchNotifications(SwitchDevice aDevice);
+    async EnableSwitchNotifications(SwitchDevice aDevice);
+    async DisableSwitchNotifications(SwitchDevice aDevice);
     sync GetCurrentSwitchState(SwitchDevice aDevice)
       returns (SwitchState aState);
 
-    FactoryReset(nsString aReason);
+    async FactoryReset(nsString aReason);
 
 child:
-    NotifySensorChange(SensorData aSensorData);
+    async NotifySensorChange(SensorData aSensorData);
 
 parent:
-    EnableSensorNotifications(SensorType aSensor);
-    DisableSensorNotifications(SensorType aSensor);
+    async EnableSensorNotifications(SensorType aSensor);
+    async DisableSensorNotifications(SensorType aSensor);
 
-    __delete__();
+    async __delete__();
 };
 
 } // namespace hal
diff --git a/ipc/glue/PBackground.ipdl b/ipc/glue/PBackground.ipdl
index 94a119d6779..9f7c2a19653 100644
--- a/ipc/glue/PBackground.ipdl
+++ b/ipc/glue/PBackground.ipdl
@@ -60,46 +60,46 @@ sync protocol PBackground
 
 parent:
   // Only called at startup during mochitests to check the basic infrastructure.
-  PBackgroundTest(nsCString testArg);
+  async PBackgroundTest(nsCString testArg);
 
-  PBackgroundIDBFactory(LoggingInfo loggingInfo);
+  async PBackgroundIDBFactory(LoggingInfo loggingInfo);
 
-  PBackgroundIndexedDBUtils();
+  async PBackgroundIndexedDBUtils();
 
-  PVsync();
+  async PVsync();
 
-  PCameras();
+  async PCameras();
 
-  PUDPSocket(OptionalPrincipalInfo pInfo, nsCString filter);
-  PBroadcastChannel(PrincipalInfo pInfo, nsCString origin, nsString channel,
-                    bool privateBrowsing);
+  async PUDPSocket(OptionalPrincipalInfo pInfo, nsCString filter);
+  async PBroadcastChannel(PrincipalInfo pInfo, nsCString origin, nsString channel,
+                          bool privateBrowsing);
 
-  PServiceWorkerManager();
+  async PServiceWorkerManager();
 
-  ShutdownServiceWorkerRegistrar();
+  async ShutdownServiceWorkerRegistrar();
 
-  PCacheStorage(Namespace aNamespace, PrincipalInfo aPrincipalInfo);
+  async PCacheStorage(Namespace aNamespace, PrincipalInfo aPrincipalInfo);
 
-  PMessagePort(nsID uuid, nsID destinationUuid, uint32_t sequenceId);
+  async PMessagePort(nsID uuid, nsID destinationUuid, uint32_t sequenceId);
 
-  PNuwa();
+  async PNuwa();
 
-  MessagePortForceClose(nsID uuid, nsID destinationUuid, uint32_t sequenceId);
+  async MessagePortForceClose(nsID uuid, nsID destinationUuid, uint32_t sequenceId);
 
-  PAsmJSCacheEntry(OpenMode openMode,
-                   WriteParams write,
-                   PrincipalInfo principalInfo);
+  async PAsmJSCacheEntry(OpenMode openMode,
+                         WriteParams write,
+                         PrincipalInfo principalInfo);
 
-  PQuota();
+  async PQuota();
 
 child:
-  PCache();
-  PCacheStreamControl();
+  async PCache();
+  async PCacheStreamControl();
 
 both:
-  PBlob(BlobConstructorParams params);
+  async PBlob(BlobConstructorParams params);
 
-  PFileDescriptorSet(FileDescriptor fd);
+  async PFileDescriptorSet(FileDescriptor fd);
 };
 
 } // namespace ipc
diff --git a/ipc/glue/PBackgroundTest.ipdl b/ipc/glue/PBackgroundTest.ipdl
index c68ac628ca3..527cd4ce7dc 100644
--- a/ipc/glue/PBackgroundTest.ipdl
+++ b/ipc/glue/PBackgroundTest.ipdl
@@ -13,7 +13,7 @@ protocol PBackgroundTest
   manager PBackground;
 
 child:
-  __delete__(nsCString testArg);
+  async __delete__(nsCString testArg);
 };
 
 } // namespace ipc
diff --git a/ipc/glue/PFileDescriptorSet.ipdl b/ipc/glue/PFileDescriptorSet.ipdl
index 4508ce8a6a7..ef366494fe3 100644
--- a/ipc/glue/PFileDescriptorSet.ipdl
+++ b/ipc/glue/PFileDescriptorSet.ipdl
@@ -13,9 +13,9 @@ protocol PFileDescriptorSet
   manager PBackground or PContent;
 
 both:
-  AddFileDescriptor(FileDescriptor fd);
+  async AddFileDescriptor(FileDescriptor fd);
 
-  __delete__();
+  async __delete__();
 };
 
 } // namespace ipc
diff --git a/ipc/ipdl/ipdl/parser.py b/ipc/ipdl/ipdl/parser.py
index a0ca80d43b7..dc715d57321 100644
--- a/ipc/ipdl/ipdl/parser.py
+++ b/ipc/ipdl/ipdl/parser.py
@@ -499,7 +499,7 @@ def p_MessageDirectionLabel(p):
         assert 0
 
 def p_MessageDecl(p):
-    """MessageDecl : OptionalSendSemanticsQual MessageBody"""
+    """MessageDecl : SendSemanticsQual MessageBody"""
     msg = p[2]
     msg.priority = p[1][0]
     msg.sendSemantics = p[1][1]
@@ -636,12 +636,6 @@ def p_Priority(p):
              'urgent': 3}
     p[0] = prios[p[1]]
 
-def p_OptionalSendSemanticsQual(p):
-    """OptionalSendSemanticsQual : SendSemanticsQual
-                                 | """
-    if 2 == len(p): p[0] = p[1]
-    else:           p[0] = [ NORMAL_PRIORITY, ASYNC ]
-
 def p_SendSemanticsQual(p):
     """SendSemanticsQual : ASYNC
                          | SYNC
diff --git a/ipc/ipdl/test/cxx/PTestActorPunning.ipdl b/ipc/ipdl/test/cxx/PTestActorPunning.ipdl
index 2c09f301297..54deb277a79 100644
--- a/ipc/ipdl/test/cxx/PTestActorPunning.ipdl
+++ b/ipc/ipdl/test/cxx/PTestActorPunning.ipdl
@@ -13,13 +13,13 @@ protocol PTestActorPunning {
     manages PTestActorPunningSub;
 
 child:
-    Start();
+    async Start();
 
 parent:
-    PTestActorPunningPunned();
-    PTestActorPunningSub();
-    Pun(PTestActorPunningSub a, Bad bad);
-    __delete__();
+    async PTestActorPunningPunned();
+    async PTestActorPunningSub();
+    async Pun(PTestActorPunningSub a, Bad bad);
+    async __delete__();
 
 
 state PING:
diff --git a/ipc/ipdl/test/cxx/PTestActorPunningPunned.ipdl b/ipc/ipdl/test/cxx/PTestActorPunningPunned.ipdl
index 219dc2b0279..a6b875920ef 100644
--- a/ipc/ipdl/test/cxx/PTestActorPunningPunned.ipdl
+++ b/ipc/ipdl/test/cxx/PTestActorPunningPunned.ipdl
@@ -8,7 +8,7 @@ protocol PTestActorPunningPunned {
     manager PTestActorPunning;
 
 child:
-    __delete__();
+    async __delete__();
 };
 
 } // namespace mozilla
diff --git a/ipc/ipdl/test/cxx/PTestActorPunningSub.ipdl b/ipc/ipdl/test/cxx/PTestActorPunningSub.ipdl
index c466d8578e5..1441219c385 100644
--- a/ipc/ipdl/test/cxx/PTestActorPunningSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestActorPunningSub.ipdl
@@ -8,8 +8,8 @@ protocol PTestActorPunningSub {
     manager PTestActorPunning;
 
 child:
-    Bad();
-    __delete__();
+    async Bad();
+    async __delete__();
 };
 
 } // namespace mozilla
diff --git a/ipc/ipdl/test/cxx/PTestBadActor.ipdl b/ipc/ipdl/test/cxx/PTestBadActor.ipdl
index 1e9f25e6719..841d89ff631 100644
--- a/ipc/ipdl/test/cxx/PTestBadActor.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBadActor.ipdl
@@ -10,8 +10,8 @@ intr protocol PTestBadActor {
   manages PTestBadActorSub;
 
 child:
-  PTestBadActorSub();
-  __delete__();
+  async PTestBadActorSub();
+  async __delete__();
 };
 
 } // namespace _ipdltest
diff --git a/ipc/ipdl/test/cxx/PTestBadActorSub.ipdl b/ipc/ipdl/test/cxx/PTestBadActorSub.ipdl
index 6baf777edd0..99c78f4ac97 100644
--- a/ipc/ipdl/test/cxx/PTestBadActorSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBadActorSub.ipdl
@@ -10,7 +10,7 @@ child:
   intr __delete__();
 
 parent:
-  Ping();
+  async Ping();
 };
 
 } // namespace _ipdltest
diff --git a/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl b/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
index 77b9024bf1e..229820b1728 100644
--- a/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBridgeMain.ipdl
@@ -10,10 +10,10 @@ protocol PTestBridgeMain {
     child opens PTestBridgeMainSub;
 
 child:
-    Start();
+    async Start();
 
 parent:
-    __delete__();
+    async __delete__();
 
 state START:
     send Start goto DEAD;
diff --git a/ipc/ipdl/test/cxx/PTestBridgeMainSub.ipdl b/ipc/ipdl/test/cxx/PTestBridgeMainSub.ipdl
index 7f672b56ae6..67e50fdd46b 100644
--- a/ipc/ipdl/test/cxx/PTestBridgeMainSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBridgeMainSub.ipdl
@@ -10,14 +10,14 @@ intr protocol PTestBridgeMainSub {
     bridges PTestBridgeMain, PTestBridgeSub;
 
 child:
-    Hi();
+    async Hi();
     intr HiRpc();
 
 parent:
-    Hello();
+    async Hello();
     sync HelloSync();
     intr HelloRpc();
-    __delete__();
+    async __delete__();
 
 state START:       recv Hello goto HI;
 state HI:          send Hi goto HELLO_SYNC;
diff --git a/ipc/ipdl/test/cxx/PTestBridgeSub.ipdl b/ipc/ipdl/test/cxx/PTestBridgeSub.ipdl
index fc2d4f4f002..6c798c84e5f 100644
--- a/ipc/ipdl/test/cxx/PTestBridgeSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestBridgeSub.ipdl
@@ -6,11 +6,11 @@ namespace _ipdltest {
 
 protocol PTestBridgeSub {
 child:
-    Ping();
+    async Ping();
 
 parent:
-    BridgeEm();
-    __delete__();
+    async BridgeEm();
+    async __delete__();
 
 state START:
     send Ping goto BRIDGEEM;
diff --git a/ipc/ipdl/test/cxx/PTestCrashCleanup.ipdl b/ipc/ipdl/test/cxx/PTestCrashCleanup.ipdl
index d0acda8707f..eae428211f7 100644
--- a/ipc/ipdl/test/cxx/PTestCrashCleanup.ipdl
+++ b/ipc/ipdl/test/cxx/PTestCrashCleanup.ipdl
@@ -10,7 +10,7 @@ namespace _ipdltest {
 intr protocol PTestCrashCleanup {
 child:
     intr DIEDIEDIE();
-    __delete__();
+    async __delete__();
 
 state ALIVE:
     call DIEDIEDIE goto CRASH;
diff --git a/ipc/ipdl/test/cxx/PTestDataStructures.ipdl b/ipc/ipdl/test/cxx/PTestDataStructures.ipdl
index b0aacb99138..59bf74652ff 100644
--- a/ipc/ipdl/test/cxx/PTestDataStructures.ipdl
+++ b/ipc/ipdl/test/cxx/PTestDataStructures.ipdl
@@ -10,12 +10,12 @@ sync protocol PTestDataStructures {
     manages PTestDataStructuresSub;
 
 child:
-    PTestDataStructuresSub(int i);
+    async PTestDataStructuresSub(int i);
 
-    Start();
+    async Start();
 
 parent:
-    __delete__();
+    async __delete__();
 
     sync Test1(int[] i1)
         returns (int[] o1);
diff --git a/ipc/ipdl/test/cxx/PTestDesc.ipdl b/ipc/ipdl/test/cxx/PTestDesc.ipdl
index fdcc63805b8..835c8c62d25 100644
--- a/ipc/ipdl/test/cxx/PTestDesc.ipdl
+++ b/ipc/ipdl/test/cxx/PTestDesc.ipdl
@@ -9,12 +9,12 @@ intr protocol PTestDesc {
 child:
     intr PTestDescSub(nullable PTestDescSubsub dummy);
 
-    Test(PTestDescSubsub a);
+    async Test(PTestDescSubsub a);
 
-    __delete__();
+    async __delete__();
 
 parent:
-    Ok(PTestDescSubsub a);
+    async Ok(PTestDescSubsub a);
 
 
 state CONSTRUCT:
diff --git a/ipc/ipdl/test/cxx/PTestDescSub.ipdl b/ipc/ipdl/test/cxx/PTestDescSub.ipdl
index c4a70cfcf37..67d4fe1660f 100644
--- a/ipc/ipdl/test/cxx/PTestDescSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestDescSub.ipdl
@@ -9,7 +9,7 @@ intr protocol PTestDescSub {
     manages PTestDescSubsub;
 
 child:
-    __delete__();
+    async __delete__();
 
     intr PTestDescSubsub();
 };
diff --git a/ipc/ipdl/test/cxx/PTestEndpointBridgeMain.ipdl b/ipc/ipdl/test/cxx/PTestEndpointBridgeMain.ipdl
index d27757ed12e..e8026a0d0f6 100644
--- a/ipc/ipdl/test/cxx/PTestEndpointBridgeMain.ipdl
+++ b/ipc/ipdl/test/cxx/PTestEndpointBridgeMain.ipdl
@@ -12,10 +12,10 @@ protocol PTestEndpointBridgeMain {
   child spawns PTestEndpointBridgeSub;
 
 child:
-  Start();
+  async Start();
 
 parent:
-  Bridged(Endpoint<PTestEndpointBridgeMainSubParent> endpoint);
+  async Bridged(Endpoint<PTestEndpointBridgeMainSubParent> endpoint);
 };
 
 
diff --git a/ipc/ipdl/test/cxx/PTestEndpointBridgeMainSub.ipdl b/ipc/ipdl/test/cxx/PTestEndpointBridgeMainSub.ipdl
index d0db5dc1709..7364057acc2 100644
--- a/ipc/ipdl/test/cxx/PTestEndpointBridgeMainSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestEndpointBridgeMainSub.ipdl
@@ -11,11 +11,11 @@ namespace _ipdltest {
 // they bridge)
 intr protocol PTestEndpointBridgeMainSub {
 child:
-  Hi();
+  async Hi();
   intr HiRpc();
 
 parent:
-  Hello();
+  async Hello();
   sync HelloSync();
   intr HelloRpc();
 };
diff --git a/ipc/ipdl/test/cxx/PTestEndpointBridgeSub.ipdl b/ipc/ipdl/test/cxx/PTestEndpointBridgeSub.ipdl
index 17ba5f2dc2a..0bc09b70e1c 100644
--- a/ipc/ipdl/test/cxx/PTestEndpointBridgeSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestEndpointBridgeSub.ipdl
@@ -9,12 +9,12 @@ namespace _ipdltest {
 
 protocol PTestEndpointBridgeSub {
 child:
-  Ping();
+  async Ping();
 
-  Bridged(Endpoint<PTestEndpointBridgeMainSubChild> endpoint);
+  async Bridged(Endpoint<PTestEndpointBridgeMainSubChild> endpoint);
 
 parent:
-  BridgeEm();
+  async BridgeEm();
 };
 
 
diff --git a/ipc/ipdl/test/cxx/PTestEndpointOpens.ipdl b/ipc/ipdl/test/cxx/PTestEndpointOpens.ipdl
index 5b878752834..7be99ddd2bf 100644
--- a/ipc/ipdl/test/cxx/PTestEndpointOpens.ipdl
+++ b/ipc/ipdl/test/cxx/PTestEndpointOpens.ipdl
@@ -7,12 +7,12 @@ namespace _ipdltest {
 
 protocol PTestEndpointOpens {
 child:
-  Start();
+  async Start();
 
 parent:
-  StartSubprotocol(Endpoint<PTestEndpointOpensOpenedParent> endpoint);
+  async StartSubprotocol(Endpoint<PTestEndpointOpensOpenedParent> endpoint);
 
-  __delete__();
+  async __delete__();
 };
 
 } // namespace mozilla
diff --git a/ipc/ipdl/test/cxx/PTestEndpointOpensOpened.ipdl b/ipc/ipdl/test/cxx/PTestEndpointOpensOpened.ipdl
index a4bc3f7d01c..e14c0cb8a6c 100644
--- a/ipc/ipdl/test/cxx/PTestEndpointOpensOpened.ipdl
+++ b/ipc/ipdl/test/cxx/PTestEndpointOpensOpened.ipdl
@@ -7,14 +7,14 @@ namespace _ipdltest2 {
 // that opened them)
 intr protocol PTestEndpointOpensOpened {
 child:
-    Hi();
+    async Hi();
     intr HiRpc();
 
 parent:
-    Hello();
+    async Hello();
     sync HelloSync();
     intr HelloRpc();
-    __delete__();
+    async __delete__();
 
 state START:       recv Hello goto HI;
 state HI:          send Hi goto HELLO_SYNC;
diff --git a/ipc/ipdl/test/cxx/PTestFailedCtor.ipdl b/ipc/ipdl/test/cxx/PTestFailedCtor.ipdl
index 1dee1f46d33..94b9da08118 100644
--- a/ipc/ipdl/test/cxx/PTestFailedCtor.ipdl
+++ b/ipc/ipdl/test/cxx/PTestFailedCtor.ipdl
@@ -7,7 +7,7 @@ intr protocol PTestFailedCtor {
     manages PTestFailedCtorSub; 
 child:
     intr PTestFailedCtorSub();
-    __delete__();
+    async __delete__();
 
 state CONSTRUCT:
     call PTestFailedCtorSub goto DEAD;
diff --git a/ipc/ipdl/test/cxx/PTestFailedCtorSub.ipdl b/ipc/ipdl/test/cxx/PTestFailedCtorSub.ipdl
index 42fca117551..b1d18a05fdb 100644
--- a/ipc/ipdl/test/cxx/PTestFailedCtorSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestFailedCtorSub.ipdl
@@ -11,7 +11,7 @@ intr protocol PTestFailedCtorSub {
 parent:
     async PTestFailedCtorSubsub();
     sync Sync();
-    __delete__();
+    async __delete__();
 };
 
 }
diff --git a/ipc/ipdl/test/cxx/PTestFailedCtorSubsub.ipdl b/ipc/ipdl/test/cxx/PTestFailedCtorSubsub.ipdl
index ca272e17b8c..654170d9760 100644
--- a/ipc/ipdl/test/cxx/PTestFailedCtorSubsub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestFailedCtorSubsub.ipdl
@@ -8,7 +8,7 @@ intr protocol PTestFailedCtorSubsub {
     manager PTestFailedCtorSub;
 
 parent:
-     __delete__();
+     async __delete__();
 };
 
 }
diff --git a/ipc/ipdl/test/cxx/PTestHandle.ipdl b/ipc/ipdl/test/cxx/PTestHandle.ipdl
index edf8d39637e..aad92bae18d 100644
--- a/ipc/ipdl/test/cxx/PTestHandle.ipdl
+++ b/ipc/ipdl/test/cxx/PTestHandle.ipdl
@@ -7,7 +7,7 @@ protocol PTestHandle {
     manager PTestJSON;
 
 child:
-    __delete__();
+    async __delete__();
 };
 
 } // namespace mozilla
diff --git a/ipc/ipdl/test/cxx/PTestHangs.ipdl b/ipc/ipdl/test/cxx/PTestHangs.ipdl
index d32996101d3..b1b43fa754a 100644
--- a/ipc/ipdl/test/cxx/PTestHangs.ipdl
+++ b/ipc/ipdl/test/cxx/PTestHangs.ipdl
@@ -12,7 +12,7 @@ parent:
 child:
     async Start();
     intr Hang();
-    __delete__();
+    async __delete__();
 
 
 state START:
diff --git a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamFirst.ipdl b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamFirst.ipdl
index 4d451e64721..228ec04e88d 100644
--- a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamFirst.ipdl
+++ b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamFirst.ipdl
@@ -12,7 +12,7 @@ sync protocol PTestIndirectProtocolParamFirst {
 parent:
     sync Test(IndirectParamUnion actor);
 both:
-    __delete__();
+    async __delete__();
 };
 
 }
diff --git a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamManage.ipdl b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamManage.ipdl
index a95dc84184f..db7c828a228 100644
--- a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamManage.ipdl
+++ b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamManage.ipdl
@@ -8,9 +8,9 @@ sync protocol PTestIndirectProtocolParamManage {
     manages PTestIndirectProtocolParamFirst;
     manages PTestIndirectProtocolParamSecond;
 both:
-    PTestIndirectProtocolParamFirst();
-    PTestIndirectProtocolParamSecond();
-    __delete__();
+    async PTestIndirectProtocolParamFirst();
+    async PTestIndirectProtocolParamSecond();
+    async __delete__();
 };
 
 }
diff --git a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamSecond.ipdl b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamSecond.ipdl
index a288b5be8a7..ed21f58f883 100644
--- a/ipc/ipdl/test/cxx/PTestIndirectProtocolParamSecond.ipdl
+++ b/ipc/ipdl/test/cxx/PTestIndirectProtocolParamSecond.ipdl
@@ -6,7 +6,7 @@ namespace _ipdltest {
 sync protocol PTestIndirectProtocolParamSecond {
     manager PTestIndirectProtocolParamManage;
 both:
-    __delete__();
+    async __delete__();
 };
 
 }
diff --git a/ipc/ipdl/test/cxx/PTestInterruptRaces.ipdl b/ipc/ipdl/test/cxx/PTestInterruptRaces.ipdl
index 3fb07f1a770..bf71a251c74 100644
--- a/ipc/ipdl/test/cxx/PTestInterruptRaces.ipdl
+++ b/ipc/ipdl/test/cxx/PTestInterruptRaces.ipdl
@@ -13,11 +13,11 @@ parent:
     sync GetAnsweredParent() returns (bool answeredParent);
 
 child:
-    Start();
-    Wakeup();
-    Wakeup3();
+    async Start();
+    async Wakeup();
+    async Wakeup3();
     intr Child();
-    __delete__();
+    async __delete__();
 
 state START:
     send Start goto TEST1;
diff --git a/ipc/ipdl/test/cxx/PTestLatency.ipdl b/ipc/ipdl/test/cxx/PTestLatency.ipdl
index 438f2ffa5f2..d0c9750d8e5 100644
--- a/ipc/ipdl/test/cxx/PTestLatency.ipdl
+++ b/ipc/ipdl/test/cxx/PTestLatency.ipdl
@@ -6,19 +6,19 @@ namespace _ipdltest {
 intr protocol PTestLatency {
 
 child:
-    __delete__();
-    Ping();
-    Ping5();
+    async __delete__();
+    async Ping();
+    async Ping5();
     intr Rpc();
-    Spam();
+    async Spam();
     intr Synchro();
-    CompressedSpam(uint32_t seqno) compress;
+    async CompressedSpam(uint32_t seqno) compress;
     intr Synchro2() returns (uint32_t lastSeqno,
                             uint32_t numMessagesDispatched);
 
 parent:
-    Pong();
-    Pong5();
+    async Pong();
+    async Pong5();
 
 state START:
     // if the timing resolution is too low, abort the test
diff --git a/ipc/ipdl/test/cxx/PTestManyChildAllocs.ipdl b/ipc/ipdl/test/cxx/PTestManyChildAllocs.ipdl
index e1a332c7957..767af85a20c 100644
--- a/ipc/ipdl/test/cxx/PTestManyChildAllocs.ipdl
+++ b/ipc/ipdl/test/cxx/PTestManyChildAllocs.ipdl
@@ -7,12 +7,12 @@ protocol PTestManyChildAllocs {
     manages PTestManyChildAllocsSub;
 
 child:
-    Go();                       // start allocating
+    async Go();                       // start allocating
 
 parent:
-    Done();
+    async Done();
 
-    PTestManyChildAllocsSub();
+    async PTestManyChildAllocsSub();
 };
 
 } // namespace _ipdltest
diff --git a/ipc/ipdl/test/cxx/PTestManyChildAllocsSub.ipdl b/ipc/ipdl/test/cxx/PTestManyChildAllocsSub.ipdl
index 44fa7f7f35d..e3d9c98df9d 100644
--- a/ipc/ipdl/test/cxx/PTestManyChildAllocsSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestManyChildAllocsSub.ipdl
@@ -7,10 +7,10 @@ protocol PTestManyChildAllocsSub {
     manager PTestManyChildAllocs;
 
 child:
-    __delete__();
+    async __delete__();
 
 parent:
-    Hello();
+    async Hello();
 
     // empty
 };
diff --git a/ipc/ipdl/test/cxx/PTestMultiMgrs.ipdl b/ipc/ipdl/test/cxx/PTestMultiMgrs.ipdl
index 8c45b397e64..6322bb1a3eb 100644
--- a/ipc/ipdl/test/cxx/PTestMultiMgrs.ipdl
+++ b/ipc/ipdl/test/cxx/PTestMultiMgrs.ipdl
@@ -9,13 +9,13 @@ protocol PTestMultiMgrs {
     manages PTestMultiMgrsRight;
 
 parent:
-    OK();
+    async OK();
 
 child:
-    PTestMultiMgrsLeft();
-    PTestMultiMgrsRight();
-    Check();
-    __delete__();
+    async PTestMultiMgrsLeft();
+    async PTestMultiMgrsRight();
+    async Check();
+    async __delete__();
 
 state START:
     send PTestMultiMgrsLeft goto CONSTRUCT_RIGHT;
diff --git a/ipc/ipdl/test/cxx/PTestMultiMgrsBottom.ipdl b/ipc/ipdl/test/cxx/PTestMultiMgrsBottom.ipdl
index 8fbda67da98..9c474f446f8 100644
--- a/ipc/ipdl/test/cxx/PTestMultiMgrsBottom.ipdl
+++ b/ipc/ipdl/test/cxx/PTestMultiMgrsBottom.ipdl
@@ -8,7 +8,7 @@ protocol PTestMultiMgrsBottom {
     manager PTestMultiMgrsLeft or PTestMultiMgrsRight;
 
 child:
-    __delete__();
+    async __delete__();
 
 state DOA:
     send __delete__;
diff --git a/ipc/ipdl/test/cxx/PTestMultiMgrsLeft.ipdl b/ipc/ipdl/test/cxx/PTestMultiMgrsLeft.ipdl
index 92454b0f3b4..83017627242 100644
--- a/ipc/ipdl/test/cxx/PTestMultiMgrsLeft.ipdl
+++ b/ipc/ipdl/test/cxx/PTestMultiMgrsLeft.ipdl
@@ -10,8 +10,8 @@ protocol PTestMultiMgrsLeft {
     manages PTestMultiMgrsBottom;
 
 child:
-    PTestMultiMgrsBottom();
-    __delete__();
+    async PTestMultiMgrsBottom();
+    async __delete__();
 
 state START:
     send PTestMultiMgrsBottom goto DONE;
diff --git a/ipc/ipdl/test/cxx/PTestMultiMgrsRight.ipdl b/ipc/ipdl/test/cxx/PTestMultiMgrsRight.ipdl
index 4b004f0fd1e..36b0771b77a 100644
--- a/ipc/ipdl/test/cxx/PTestMultiMgrsRight.ipdl
+++ b/ipc/ipdl/test/cxx/PTestMultiMgrsRight.ipdl
@@ -10,8 +10,8 @@ protocol PTestMultiMgrsRight {
     manages PTestMultiMgrsBottom;
 
 child:
-    PTestMultiMgrsBottom();
-    __delete__();
+    async PTestMultiMgrsBottom();
+    async __delete__();
 
 state START:
     send PTestMultiMgrsBottom goto DONE;
diff --git a/ipc/ipdl/test/cxx/PTestNestedLoops.ipdl b/ipc/ipdl/test/cxx/PTestNestedLoops.ipdl
index c8e8c8fe16a..f0f067e0b23 100644
--- a/ipc/ipdl/test/cxx/PTestNestedLoops.ipdl
+++ b/ipc/ipdl/test/cxx/PTestNestedLoops.ipdl
@@ -8,7 +8,7 @@ intr protocol PTestNestedLoops {
 child:
     async Start();
     intr R();
-    __delete__();
+    async __delete__();
 
 parent:
     async Nonce();
diff --git a/ipc/ipdl/test/cxx/PTestOpens.ipdl b/ipc/ipdl/test/cxx/PTestOpens.ipdl
index f0562d22eec..2717328faa3 100644
--- a/ipc/ipdl/test/cxx/PTestOpens.ipdl
+++ b/ipc/ipdl/test/cxx/PTestOpens.ipdl
@@ -9,10 +9,10 @@ protocol PTestOpens {
     child opens PTestOpensOpened;
 
 child:
-    Start();
+    async Start();
 
 parent:
-    __delete__();
+    async __delete__();
 
 state START:
     send Start goto DEAD;
diff --git a/ipc/ipdl/test/cxx/PTestOpensOpened.ipdl b/ipc/ipdl/test/cxx/PTestOpensOpened.ipdl
index f6cdfeb4adc..04b633634ad 100644
--- a/ipc/ipdl/test/cxx/PTestOpensOpened.ipdl
+++ b/ipc/ipdl/test/cxx/PTestOpensOpened.ipdl
@@ -5,14 +5,14 @@ namespace _ipdltest2 {
 // that opened them)
 intr protocol PTestOpensOpened {
 child:
-    Hi();
+    async Hi();
     intr HiRpc();
 
 parent:
-    Hello();
+    async Hello();
     sync HelloSync();
     intr HelloRpc();
-    __delete__();
+    async __delete__();
 
 state START:       recv Hello goto HI;
 state HI:          send Hi goto HELLO_SYNC;
diff --git a/ipc/ipdl/test/cxx/PTestRacyReentry.ipdl b/ipc/ipdl/test/cxx/PTestRacyReentry.ipdl
index 6862527398d..4dd5fe54fbd 100644
--- a/ipc/ipdl/test/cxx/PTestRacyReentry.ipdl
+++ b/ipc/ipdl/test/cxx/PTestRacyReentry.ipdl
@@ -7,7 +7,7 @@ intr protocol PTestRacyReentry {
 
 parent:
     intr E();
-    __delete__();
+    async __delete__();
 
 child:
     async Start();
diff --git a/ipc/ipdl/test/cxx/PTestSanity.ipdl b/ipc/ipdl/test/cxx/PTestSanity.ipdl
index e143e3381c8..50249b7414e 100644
--- a/ipc/ipdl/test/cxx/PTestSanity.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSanity.ipdl
@@ -6,11 +6,11 @@ namespace _ipdltest {
 protocol PTestSanity {
 
 child:
-    Ping(int zero, float zeroPtFive, int8_t dummy);
-    __delete__();
+    async Ping(int zero, float zeroPtFive, int8_t dummy);
+    async __delete__();
 
 parent:
-    Pong(int one, float zeroPtTwoFive, uint8_t dummy);
+    async Pong(int one, float zeroPtTwoFive, uint8_t dummy);
 
 
 state PING:
diff --git a/ipc/ipdl/test/cxx/PTestSelfManage.ipdl b/ipc/ipdl/test/cxx/PTestSelfManage.ipdl
index f0b1e451008..69eb4f55c59 100644
--- a/ipc/ipdl/test/cxx/PTestSelfManage.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSelfManage.ipdl
@@ -9,8 +9,8 @@ protocol PTestSelfManage {
     manages PTestSelfManage;
 
 child:
-    PTestSelfManage();
-    __delete__();
+    async PTestSelfManage();
+    async __delete__();
 
 state LIVE:
     send PTestSelfManage goto LIVE;
diff --git a/ipc/ipdl/test/cxx/PTestSelfManageRoot.ipdl b/ipc/ipdl/test/cxx/PTestSelfManageRoot.ipdl
index 12dc687bd6f..429f8bfc80b 100644
--- a/ipc/ipdl/test/cxx/PTestSelfManageRoot.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSelfManageRoot.ipdl
@@ -8,8 +8,8 @@ protocol PTestSelfManageRoot {
     manages PTestSelfManage;
 
 child:
-    PTestSelfManage();
-    __delete__();
+    async PTestSelfManage();
+    async __delete__();
 
 state LIVE:
     send PTestSelfManage goto DEAD;
diff --git a/ipc/ipdl/test/cxx/PTestShmem.ipdl b/ipc/ipdl/test/cxx/PTestShmem.ipdl
index 19eebaed4fe..46a1958e280 100644
--- a/ipc/ipdl/test/cxx/PTestShmem.ipdl
+++ b/ipc/ipdl/test/cxx/PTestShmem.ipdl
@@ -3,11 +3,11 @@ namespace _ipdltest {
 
 protocol PTestShmem {
 child:
-    Give(Shmem mem, Shmem unsafe, size_t expectedSize);
+    async Give(Shmem mem, Shmem unsafe, size_t expectedSize);
 
 parent:
-    Take(Shmem mem, Shmem unsafe, size_t expectedSize);
-    __delete__();
+    async Take(Shmem mem, Shmem unsafe, size_t expectedSize);
+    async __delete__();
 
 
 state GIVING:
diff --git a/ipc/ipdl/test/cxx/PTestShutdown.ipdl b/ipc/ipdl/test/cxx/PTestShutdown.ipdl
index 3f79809d2a4..e4d8d0dbebe 100644
--- a/ipc/ipdl/test/cxx/PTestShutdown.ipdl
+++ b/ipc/ipdl/test/cxx/PTestShutdown.ipdl
@@ -7,19 +7,19 @@ intr protocol PTestShutdown {
     manages PTestShutdownSub;
 
 child:
-    Start();
+    async Start();
 
 parent:
     // NB: we test deletion and crashing only, not shutdown, because
     // crashing is the same code path as shutdown, and other IPDL unit
     // tests check shutdown semantics
-    PTestShutdownSub(bool expectCrash);
+    async PTestShutdownSub(bool expectCrash);
 
     // Used to synchronize between parent and child, to avoid races
     // around flushing socket write queues
     sync Sync();
 
-    __delete__();
+    async __delete__();
 
 
 state START:
diff --git a/ipc/ipdl/test/cxx/PTestShutdownSub.ipdl b/ipc/ipdl/test/cxx/PTestShutdownSub.ipdl
index 6061d0685af..39d45d9ed82 100644
--- a/ipc/ipdl/test/cxx/PTestShutdownSub.ipdl
+++ b/ipc/ipdl/test/cxx/PTestShutdownSub.ipdl
@@ -12,7 +12,7 @@ both:
     intr StackFrame();
 
 parent:
-    PTestShutdownSubsub(bool expectParentDeleted);
+    async PTestShutdownSubsub(bool expectParentDeleted);
     sync __delete__();
 
 state CREATING:
diff --git a/ipc/ipdl/test/cxx/PTestStackHooks.ipdl b/ipc/ipdl/test/cxx/PTestStackHooks.ipdl
index 3f79d1a5d3e..1f3af068fba 100644
--- a/ipc/ipdl/test/cxx/PTestStackHooks.ipdl
+++ b/ipc/ipdl/test/cxx/PTestStackHooks.ipdl
@@ -18,7 +18,7 @@ both:
     intr StackFrame();
 
 parent:
-    __delete__();
+    async __delete__();
 
 
 state START:
diff --git a/ipc/ipdl/test/cxx/PTestSyncError.ipdl b/ipc/ipdl/test/cxx/PTestSyncError.ipdl
index 0443d7d4d58..05b68ff3509 100644
--- a/ipc/ipdl/test/cxx/PTestSyncError.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSyncError.ipdl
@@ -6,11 +6,11 @@ namespace _ipdltest {
 sync protocol PTestSyncError {
 
 child:
-    Start();
+    async Start();
 
 parent:
     sync Error();
-    __delete__();
+    async __delete__();
 
 
 state START:
diff --git a/ipc/ipdl/test/cxx/PTestSyncHang.ipdl b/ipc/ipdl/test/cxx/PTestSyncHang.ipdl
index 861825d5c9b..eefcf2c5e95 100644
--- a/ipc/ipdl/test/cxx/PTestSyncHang.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSyncHang.ipdl
@@ -6,7 +6,7 @@ namespace _ipdltest {
 protocol PTestSyncHang {
 
 child:
-    __delete__();
+    async __delete__();
 
 };
 
diff --git a/ipc/ipdl/test/cxx/PTestSysVShmem.ipdl b/ipc/ipdl/test/cxx/PTestSysVShmem.ipdl
index b5567c78634..56c01c54a74 100644
--- a/ipc/ipdl/test/cxx/PTestSysVShmem.ipdl
+++ b/ipc/ipdl/test/cxx/PTestSysVShmem.ipdl
@@ -3,11 +3,11 @@ namespace _ipdltest {
 
 protocol PTestSysVShmem {
 child:
-    Give(Shmem mem, Shmem unsafe, size_t expectedSize);
+    async Give(Shmem mem, Shmem unsafe, size_t expectedSize);
 
 parent:
-    Take(Shmem mem, Shmem unsafe, size_t expectedSize);
-    __delete__();
+    async Take(Shmem mem, Shmem unsafe, size_t expectedSize);
+    async __delete__();
 
 
 state GIVING:
diff --git a/ipc/ipdl/test/ipdl/error/DeleteRace.ipdl b/ipc/ipdl/test/ipdl/error/DeleteRace.ipdl
index 27754e39b6a..992bbabdf2f 100644
--- a/ipc/ipdl/test/ipdl/error/DeleteRace.ipdl
+++ b/ipc/ipdl/test/ipdl/error/DeleteRace.ipdl
@@ -3,10 +3,10 @@
 // we'll notice, right?
 protocol DeleteRace {
 parent:
-    M1();
+    async M1();
 
 child:
-    __delete__();
+    async __delete__();
 
 state START:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/error/Nullable.ipdl b/ipc/ipdl/test/ipdl/error/Nullable.ipdl
index a7211b0893a..cb7097f0e15 100644
--- a/ipc/ipdl/test/ipdl/error/Nullable.ipdl
+++ b/ipc/ipdl/test/ipdl/error/Nullable.ipdl
@@ -1,4 +1,4 @@
 protocol Nullable {
 child:
-    Msg(nullable int i);
+    async Msg(nullable int i);
 };
diff --git a/ipc/ipdl/test/ipdl/error/Nullable2.ipdl b/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
index 40125814037..d572951aeab 100644
--- a/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
+++ b/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
@@ -4,5 +4,5 @@ union Union {
 
 protocol Nullable2 {
 child:
-    Msg(Union i);
+    async Msg(Union i);
 };
diff --git a/ipc/ipdl/test/ipdl/error/actorparam_badState.ipdl b/ipc/ipdl/test/ipdl/error/actorparam_badState.ipdl
index f6ac49efac0..93b8ba21862 100644
--- a/ipc/ipdl/test/ipdl/error/actorparam_badState.ipdl
+++ b/ipc/ipdl/test/ipdl/error/actorparam_badState.ipdl
@@ -1,8 +1,8 @@
 protocol actorparam_badState {
 
 child:
-    Msg(actorparam_badState:FARGEL p);
-    __delete__();
+    async Msg(actorparam_badState:FARGEL p);
+    async __delete__();
 
 state S1:
     send Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/bridgesSubprotocol.ipdl b/ipc/ipdl/test/ipdl/error/bridgesSubprotocol.ipdl
index 8918a08be19..a07c295d94d 100644
--- a/ipc/ipdl/test/ipdl/error/bridgesSubprotocol.ipdl
+++ b/ipc/ipdl/test/ipdl/error/bridgesSubprotocol.ipdl
@@ -7,7 +7,7 @@ protocol bridgesSubprotocol {
 
 child:
     subprotocolBridges();
-    __delete__();
+    async __delete__();
 
 state DEAD: send __delete__;
 };
diff --git a/ipc/ipdl/test/ipdl/error/cyclecheck_Child.ipdl b/ipc/ipdl/test/ipdl/error/cyclecheck_Child.ipdl
index b1c15cd90c6..2e1b93299a9 100644
--- a/ipc/ipdl/test/ipdl/error/cyclecheck_Child.ipdl
+++ b/ipc/ipdl/test/ipdl/error/cyclecheck_Child.ipdl
@@ -7,6 +7,6 @@ protocol cyclecheck_Child {
 
 child:
     cyclecheck_Grandchild();
-    __delete__();
+    async __delete__();
 };
 
diff --git a/ipc/ipdl/test/ipdl/error/cyclecheck_Grandchild.ipdl b/ipc/ipdl/test/ipdl/error/cyclecheck_Grandchild.ipdl
index f16f2f98b8e..d91949de458 100644
--- a/ipc/ipdl/test/ipdl/error/cyclecheck_Grandchild.ipdl
+++ b/ipc/ipdl/test/ipdl/error/cyclecheck_Grandchild.ipdl
@@ -7,6 +7,6 @@ protocol cyclecheck_Grandchild {
 
 child:
     cyclecheck_Parent();
-    __delete__();
+    async __delete__();
 };
 
diff --git a/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl b/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
index b9f0630e216..666d44c54be 100644
--- a/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
+++ b/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
@@ -5,6 +5,6 @@ protocol cyclecheck_Parent {
 
 child:
     cyclecheck_Child();
-    __delete__();
+    async __delete__();
 };
 
diff --git a/ipc/ipdl/test/ipdl/error/manageSelfToplevel.ipdl b/ipc/ipdl/test/ipdl/error/manageSelfToplevel.ipdl
index 9dcf970a834..d7088912656 100644
--- a/ipc/ipdl/test/ipdl/error/manageSelfToplevel.ipdl
+++ b/ipc/ipdl/test/ipdl/error/manageSelfToplevel.ipdl
@@ -4,5 +4,5 @@ protocol manageSelfToplevel {
 
 child:
     manageSelfToplevel();
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl b/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
index 69a89e75209..a3d9585d4d1 100644
--- a/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
+++ b/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
@@ -1,3 +1,3 @@
 protocol messageNoDirection {
-    NoDirection();
+    async NoDirection();
 };
diff --git a/ipc/ipdl/test/ipdl/error/multimanDupMgrs.ipdl b/ipc/ipdl/test/ipdl/error/multimanDupMgrs.ipdl
index 7bc9b2cfe49..eb89f77d807 100644
--- a/ipc/ipdl/test/ipdl/error/multimanDupMgrs.ipdl
+++ b/ipc/ipdl/test/ipdl/error/multimanDupMgrs.ipdl
@@ -4,5 +4,5 @@ protocol multimanDupMgrs {
     manager multimanDupMgrsMgr or multimanDupMgrsMgr;
 
 child:
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl b/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
index 76248e025fd..be8dfbc8373 100644
--- a/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
+++ b/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
@@ -5,5 +5,5 @@ protocol multimanDupMgrsMgr {
 
 child:
     multimanDupMgrs();
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/multimanNonexistentMgrs.ipdl b/ipc/ipdl/test/ipdl/error/multimanNonexistentMgrs.ipdl
index 80aff22b7a0..dd4ba254c9e 100644
--- a/ipc/ipdl/test/ipdl/error/multimanNonexistentMgrs.ipdl
+++ b/ipc/ipdl/test/ipdl/error/multimanNonexistentMgrs.ipdl
@@ -2,6 +2,6 @@ protocol multimanNonexistentManagers {
     manager Starsky or Hutch;
 
 child:
-    Dummy();
-    __delete__();
+    async Dummy();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
index c35282de9a6..fd4ee4d18df 100644
--- a/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
@@ -15,6 +15,6 @@ struct Z {
 
 protocol mutualRecStruct {
 child:
-    Test(X x, Y y, Z z);
-    __delete__();
+    async Test(X x, Y y, Z z);
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl b/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
index 73ef4470f81..f475952d12b 100644
--- a/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
@@ -15,6 +15,6 @@ struct Z {
 
 protocol mutualRecStructUnion {
 child:
-    Test(X x, Y y, Z z);
-    __delete__();
+    async Test(X x, Y y, Z z);
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/opensSubprotocol.ipdl b/ipc/ipdl/test/ipdl/error/opensSubprotocol.ipdl
index 46e9e42b24c..af884a636d9 100644
--- a/ipc/ipdl/test/ipdl/error/opensSubprotocol.ipdl
+++ b/ipc/ipdl/test/ipdl/error/opensSubprotocol.ipdl
@@ -7,7 +7,7 @@ protocol opensSubprotocol {
 
 child:
     subprotocolOpens();
-    __delete__();
+    async __delete__();
 
 state DEAD: send __delete__;
 };
diff --git a/ipc/ipdl/test/ipdl/error/race_OverlappingMultiOut.ipdl b/ipc/ipdl/test/ipdl/error/race_OverlappingMultiOut.ipdl
index 99e324f72ab..8aa8318420a 100644
--- a/ipc/ipdl/test/ipdl/error/race_OverlappingMultiOut.ipdl
+++ b/ipc/ipdl/test/ipdl/error/race_OverlappingMultiOut.ipdl
@@ -1,12 +1,12 @@
 protocol race_OverlappingMultiOut {
 child:
-    Msg1();
-    Msg1_();
-    __delete__(); suppressUndeleteableError();
+    async Msg1();
+    async Msg1_();
+    async __delete__(); suppressUndeleteableError();
 
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
 
 start state _:
diff --git a/ipc/ipdl/test/ipdl/error/race_ViolateSameDirection.ipdl b/ipc/ipdl/test/ipdl/error/race_ViolateSameDirection.ipdl
index 1b24dd65e9d..a1f964ec7c1 100644
--- a/ipc/ipdl/test/ipdl/error/race_ViolateSameDirection.ipdl
+++ b/ipc/ipdl/test/ipdl/error/race_ViolateSameDirection.ipdl
@@ -1,11 +1,12 @@
 protocol race_ViolateSameDirection {
 child:
-    Msg1();
-    Msg1_();
-    __delete__(); suppressUndeleteableError();
+    async Msg1();
+    async Msg1_();
+    async __delete__();
+    async suppressUndeleteableError();
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
     // *** ERROR: state S7 doesn't have all-same-direction
 start state _:
diff --git a/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl b/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
index de3a482eb51..5b2cdcf7077 100644
--- a/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
@@ -3,7 +3,7 @@ protocol redeclMessage {
     // can't declare two messages with the same name
 
 child:
-    Msg();
-    Msg();
+    async Msg();
+    async Msg();
 
 };
diff --git a/ipc/ipdl/test/ipdl/error/redefState.ipdl b/ipc/ipdl/test/ipdl/error/redefState.ipdl
index 7001eb2d444..b9da7212b1a 100644
--- a/ipc/ipdl/test/ipdl/error/redefState.ipdl
+++ b/ipc/ipdl/test/ipdl/error/redefState.ipdl
@@ -2,8 +2,8 @@ protocol redefState {
 
     // error: redefining state in state machine
 child:
-    Msg();
-    __delete__();
+    async Msg();
+    async __delete__();
 
 state S1: send Msg goto S1;
 
diff --git a/ipc/ipdl/test/ipdl/error/shmem_access_union.ipdl b/ipc/ipdl/test/ipdl/error/shmem_access_union.ipdl
index 41700264453..2ed162368d2 100644
--- a/ipc/ipdl/test/ipdl/error/shmem_access_union.ipdl
+++ b/ipc/ipdl/test/ipdl/error/shmem_access_union.ipdl
@@ -4,5 +4,5 @@ union Union {
 
 protocol shmem_access_union {
 child:
-    Msg(Union u);
+    async Msg(Union u);
 };
diff --git a/ipc/ipdl/test/ipdl/error/spawnsSubprotocol.ipdl b/ipc/ipdl/test/ipdl/error/spawnsSubprotocol.ipdl
index e5051e9a0e3..fc056a25427 100644
--- a/ipc/ipdl/test/ipdl/error/spawnsSubprotocol.ipdl
+++ b/ipc/ipdl/test/ipdl/error/spawnsSubprotocol.ipdl
@@ -7,7 +7,7 @@ protocol spawnsSubprotocol {
 
 child:
     subprotocolSpawns();
-    __delete__();
+    async __delete__();
 
 state DEAD: send __delete__;
 };
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongDirection.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongDirection.ipdl
index ef129f945c1..53c2fd952c0 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongDirection.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongDirection.ipdl
@@ -1,8 +1,8 @@
 protocol trans_WrongDirection {
 
 child:
-    Msg();
-    __delete__();
+    async Msg();
+    async __delete__();
 
 state S1:
     recv Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongDirection2.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongDirection2.ipdl
index c3b737da848..c15dfa5afa4 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongDirection2.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongDirection2.ipdl
@@ -1,8 +1,8 @@
 protocol trans_WrongDirection2 {
 
 parent:
-    Msg();
-    __delete__();
+    async Msg();
+    async __delete__();
 
 state S1:
     send Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongDirection3.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongDirection3.ipdl
index f26e7f5d491..80621ecd186 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongDirection3.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongDirection3.ipdl
@@ -2,7 +2,7 @@ sync protocol trans_WrongDirection3 {
 
 parent:
     sync Msg();
-    __delete__();
+    async __delete__();
 
 state S1:
     send Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongDirection4.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongDirection4.ipdl
index 72ce44b5429..c27ad331d2e 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongDirection4.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongDirection4.ipdl
@@ -2,7 +2,7 @@ intr protocol trans_WrongDirection4 {
 
 child:
     intr Msg();
-    __delete__();
+    async __delete__();
 
 state S1:
     answer Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongDirection5.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongDirection5.ipdl
index 8fd9e066e77..7997649c8a3 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongDirection5.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongDirection5.ipdl
@@ -2,7 +2,7 @@ intr protocol trans_WrongDirection5 {
 
 parent:
     intr Msg();
-    __delete__()
+    async __delete__()
 
 state S1:
     call Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongName.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongName.ipdl
index 634a0eec8d2..a944d58793a 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongName.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongName.ipdl
@@ -1,8 +1,8 @@
 protocol trans_WrongName {
 
 child:
-    Msg();
-    __delete__();
+    async Msg();
+    async __delete__();
 
 state S1:
     call Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongName2.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongName2.ipdl
index 8ee65640747..ece935b7bf8 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongName2.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongName2.ipdl
@@ -1,8 +1,8 @@
 protocol trans_WrongName2 {
 
 parent:
-    Msg();
-    __delete__();
+    async Msg();
+    async __delete__();
 
 state S1:
     answer Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongName3.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongName3.ipdl
index 35b2b319a8a..80c54383f08 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongName3.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongName3.ipdl
@@ -2,7 +2,7 @@ sync protocol trans_WrongName3 {
 
 parent:
     sync Msg();
-    __delete__();
+    async __delete__();
 
 state S1:
     answer Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongName4.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongName4.ipdl
index f503d3e91f0..f8a9746e4b7 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongName4.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongName4.ipdl
@@ -2,7 +2,7 @@ intr protocol trans_WrongName4 {
 
 child:
     intr Msg();
-    __delete__();
+    async __delete__();
 
 state S1:
     send Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/trans_WrongName5.ipdl b/ipc/ipdl/test/ipdl/error/trans_WrongName5.ipdl
index 4578151e93f..a793905d2c7 100644
--- a/ipc/ipdl/test/ipdl/error/trans_WrongName5.ipdl
+++ b/ipc/ipdl/test/ipdl/error/trans_WrongName5.ipdl
@@ -2,7 +2,7 @@ intr protocol trans_WrongName5 {
 
 parent:
     intr Msg();
-    __delete__();
+    async __delete__();
 
 state S1:
     recv Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/error/unreachedDeleteMultiStart.ipdl b/ipc/ipdl/test/ipdl/error/unreachedDeleteMultiStart.ipdl
index 2b284f415d3..80e28a26d8d 100644
--- a/ipc/ipdl/test/ipdl/error/unreachedDeleteMultiStart.ipdl
+++ b/ipc/ipdl/test/ipdl/error/unreachedDeleteMultiStart.ipdl
@@ -1,6 +1,6 @@
 protocol unreachedDeleteMultiStart {
 child:
-    M1(); M2(); __delete__();
+    async M1(); async M2(); async __delete__();
 
 start state S1:  send M1 goto S2;
 state S2:        send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/Delete.ipdl b/ipc/ipdl/test/ipdl/ok/Delete.ipdl
index ef5c8a8841b..311d8253762 100644
--- a/ipc/ipdl/test/ipdl/ok/Delete.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Delete.ipdl
@@ -4,5 +4,5 @@ sync protocol Delete {
     manages DeleteSub;
 
 child:
-    DeleteSub();
+    async DeleteSub();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/Nullable.ipdl b/ipc/ipdl/test/ipdl/ok/Nullable.ipdl
index 4fd7b043d20..6a81e125d96 100644
--- a/ipc/ipdl/test/ipdl/ok/Nullable.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Nullable.ipdl
@@ -5,7 +5,7 @@ union Union {
 
 protocol Nullable {
 child:
-    Msg(nullable Nullable n);
-    Msg2(nullable Nullable[] N);
-    Msg3(Union u);
+    async Msg(nullable Nullable n);
+    async Msg2(nullable Nullable[] N);
+    async Msg3(Union u);
 };
diff --git a/ipc/ipdl/test/ipdl/ok/Struct.ipdl b/ipc/ipdl/test/ipdl/ok/Struct.ipdl
index 5365e292b9f..da3ca055a9e 100644
--- a/ipc/ipdl/test/ipdl/ok/Struct.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Struct.ipdl
@@ -6,5 +6,5 @@ struct S {
 sync protocol Struct {
 parent:
     sync test(S s) returns (S ss);
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/actorparam_state.ipdl b/ipc/ipdl/test/ipdl/ok/actorparam_state.ipdl
index df4a672a30c..5a3109f5fd3 100644
--- a/ipc/ipdl/test/ipdl/ok/actorparam_state.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/actorparam_state.ipdl
@@ -1,8 +1,8 @@
 protocol actorparam_state {
 
 child:
-    Msg(actorparam_state:S1 p);
-    __delete__();
+    async Msg(actorparam_state:S1 p);
+    async __delete__();
 
 state S1:
     send Msg goto S1;
diff --git a/ipc/ipdl/test/ipdl/ok/array_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/array_Basic.ipdl
index 91c3a18cd0a..391917708a8 100644
--- a/ipc/ipdl/test/ipdl/ok/array_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/array_Basic.ipdl
@@ -1,4 +1,4 @@
 protocol array_Basic {
 child:
-    Msg(int[] array);
+    async Msg(int[] array);
 };
diff --git a/ipc/ipdl/test/ipdl/ok/array_OfActors.ipdl b/ipc/ipdl/test/ipdl/ok/array_OfActors.ipdl
index 58ce63de43f..8d0c7fb6adb 100644
--- a/ipc/ipdl/test/ipdl/ok/array_OfActors.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/array_OfActors.ipdl
@@ -4,7 +4,7 @@ protocol array_OfActors {
     manages array_OfActorsSub;
 
 child:
-    Msg(array_OfActorsSub[] p);
+    async Msg(array_OfActorsSub[] p);
 
     array_OfActorsSub();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/compositor.ipdl b/ipc/ipdl/test/ipdl/ok/compositor.ipdl
index 3ee1dd5910b..3f1b1633565 100644
--- a/ipc/ipdl/test/ipdl/ok/compositor.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/compositor.ipdl
@@ -4,7 +4,7 @@ sync protocol compositor {
     bridges compositor, content;
 
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/content.ipdl b/ipc/ipdl/test/ipdl/ok/content.ipdl
index 33f6fbdfdcf..655998baccf 100644
--- a/ipc/ipdl/test/ipdl/ok/content.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/content.ipdl
@@ -10,7 +10,7 @@ sync protocol content {
     child opens media;
 
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/headerProto.ipdl b/ipc/ipdl/test/ipdl/ok/headerProto.ipdl
index e2082c8b026..0bccc38344b 100644
--- a/ipc/ipdl/test/ipdl/ok/headerProto.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/headerProto.ipdl
@@ -4,7 +4,7 @@ namespace c {
 
 protocol headerProto {
 child:
-    __delete__(foo a, baz b, Inner1 c, Inner2 d, X x);
+    async __delete__(foo a, baz b, Inner1 c, Inner2 d, X x);
 };
 
 }
diff --git a/ipc/ipdl/test/ipdl/ok/intrProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/intrProtocol.ipdl
index d0dd8e9bb34..1c9327f013f 100644
--- a/ipc/ipdl/test/ipdl/ok/intrProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/intrProtocol.ipdl
@@ -2,7 +2,7 @@ intr protocol intrProtocol {
 
     // sanity check of Interrupt protocols
 child:
-    AsyncMsg();
+    async AsyncMsg();
 
 parent:
     sync SyncMsg(int i) returns (int r);
diff --git a/ipc/ipdl/test/ipdl/ok/jetpack.ipdl b/ipc/ipdl/test/ipdl/ok/jetpack.ipdl
index 7ce2f8f3958..7cdb5c32970 100644
--- a/ipc/ipdl/test/ipdl/ok/jetpack.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/jetpack.ipdl
@@ -1,6 +1,6 @@
 sync protocol jetpack {
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/jetpackContent.ipdl b/ipc/ipdl/test/ipdl/ok/jetpackContent.ipdl
index 2957518acd5..1e19c541fa6 100644
--- a/ipc/ipdl/test/ipdl/ok/jetpackContent.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/jetpackContent.ipdl
@@ -5,7 +5,7 @@ intr protocol jetpackContent {
     bridges jetpack, content;
 
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/manageSelf.ipdl b/ipc/ipdl/test/ipdl/ok/manageSelf.ipdl
index e9e2fab14f2..b90ad7237aa 100644
--- a/ipc/ipdl/test/ipdl/ok/manageSelf.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/manageSelf.ipdl
@@ -6,5 +6,5 @@ protocol manageSelf {
 
 child:
     manageSelf();
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/manageSelf_Toplevel.ipdl b/ipc/ipdl/test/ipdl/ok/manageSelf_Toplevel.ipdl
index ebbe83b9fcf..8788338f39f 100644
--- a/ipc/ipdl/test/ipdl/ok/manageSelf_Toplevel.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/manageSelf_Toplevel.ipdl
@@ -5,5 +5,5 @@ protocol manageSelf_Toplevel {
 
 child:
     manageSelf();
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/managedProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/managedProtocol.ipdl
index e179bc18656..f59ab6651b2 100644
--- a/ipc/ipdl/test/ipdl/ok/managedProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/managedProtocol.ipdl
@@ -4,5 +4,5 @@ protocol managedProtocol {
     manager managerProtocol;
 
 child:
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/media.ipdl b/ipc/ipdl/test/ipdl/ok/media.ipdl
index 3aa209d9373..032f7df6f82 100644
--- a/ipc/ipdl/test/ipdl/ok/media.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/media.ipdl
@@ -1,6 +1,6 @@
 sync protocol media {
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/multiManaged.ipdl b/ipc/ipdl/test/ipdl/ok/multiManaged.ipdl
index d4ac1d336a8..c845d508698 100644
--- a/ipc/ipdl/test/ipdl/ok/multiManaged.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/multiManaged.ipdl
@@ -5,5 +5,5 @@ protocol multiManaged {
     manager multiManager1 or multiManager2;
 
 child:
-    __delete__();
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/multipleUsingCxxTypes.ipdl b/ipc/ipdl/test/ipdl/ok/multipleUsingCxxTypes.ipdl
index 6bdbd7843ef..045d3fa6e39 100644
--- a/ipc/ipdl/test/ipdl/ok/multipleUsingCxxTypes.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/multipleUsingCxxTypes.ipdl
@@ -3,5 +3,5 @@ using struct mozilla::void_t from "ipc/IPCMessageUtils.h";
 
 protocol multipleUsingCxxTypes {
 child:
-    Msg(void_t foo);
+    async Msg(void_t foo);
 };
diff --git a/ipc/ipdl/test/ipdl/ok/mutualRecStructUnion.ipdl b/ipc/ipdl/test/ipdl/ok/mutualRecStructUnion.ipdl
index 12ced52daef..0891d3e78e0 100644
--- a/ipc/ipdl/test/ipdl/ok/mutualRecStructUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/mutualRecStructUnion.ipdl
@@ -16,6 +16,6 @@ struct Z {
 
 protocol mutualRecStructUnion {
 child:
-    Test(X x, Y y, Z z);
-    __delete__();
+    async Test(X x, Y y, Z z);
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/mutualRecUnion.ipdl b/ipc/ipdl/test/ipdl/ok/mutualRecUnion.ipdl
index 88c6f98be70..fcd3649205c 100644
--- a/ipc/ipdl/test/ipdl/ok/mutualRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/mutualRecUnion.ipdl
@@ -15,6 +15,6 @@ union Z {
 
 protocol mutualRecUnion {
 child:
-    Test(X x, Y y, Z z);
-    __delete__();
+    async Test(X x, Y y, Z z);
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/namespace_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/namespace_Basic.ipdl
index cac963fbafb..4eee5ffd148 100644
--- a/ipc/ipdl/test/ipdl/ok/namespace_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/namespace_Basic.ipdl
@@ -5,7 +5,7 @@ namespace basic {
 protocol namespace_Basic {
 
 child:
-    Msg();
+    async Msg();
 
 };
 
diff --git a/ipc/ipdl/test/ipdl/ok/noRedeclCrossMessage.ipdl b/ipc/ipdl/test/ipdl/ok/noRedeclCrossMessage.ipdl
index 4b47dab6ff5..578ac82d8c0 100644
--- a/ipc/ipdl/test/ipdl/ok/noRedeclCrossMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/noRedeclCrossMessage.ipdl
@@ -3,7 +3,7 @@ protocol noRedeclCrossMessage {
     // each message has its own scope for param/return names
 
 child:
-    Msg1(int f);
-    Msg2(int f);
+    async Msg1(int f);
+    async Msg2(int f);
 
 };
diff --git a/ipc/ipdl/test/ipdl/ok/plugin.ipdl b/ipc/ipdl/test/ipdl/ok/plugin.ipdl
index c8d218fffec..b1e2d24a97f 100644
--- a/ipc/ipdl/test/ipdl/ok/plugin.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/plugin.ipdl
@@ -1,6 +1,6 @@
 intr protocol plugin {
 child:
-    __delete__();
+    async __delete__();
 
 state DEAD:
     send __delete__;
diff --git a/ipc/ipdl/test/ipdl/ok/race_DiamondRule1.ipdl b/ipc/ipdl/test/ipdl/ok/race_DiamondRule1.ipdl
index 5b3012a47fa..cc1a8b16af2 100644
--- a/ipc/ipdl/test/ipdl/ok/race_DiamondRule1.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/race_DiamondRule1.ipdl
@@ -1,11 +1,11 @@
 protocol race_DiamondRule1 {
 
 child:
-    Msg1();
-    Msg1_();
+    async Msg1();
+    async Msg1_();
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
     // OK: this state machine is one of the simplest that follows the
     // Diamond Rule
diff --git a/ipc/ipdl/test/ipdl/ok/race_KitchenSink.ipdl b/ipc/ipdl/test/ipdl/ok/race_KitchenSink.ipdl
index 3d6304c943b..55d674adada 100644
--- a/ipc/ipdl/test/ipdl/ok/race_KitchenSink.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/race_KitchenSink.ipdl
@@ -1,10 +1,10 @@
 protocol race_KitchenSink {
 child:
-    Msg1();
-    Msg1_();
+    async Msg1();
+    async Msg1_();
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
 
     // concatenation of a few other state machines, should be OK
diff --git a/ipc/ipdl/test/ipdl/ok/race_MultiOut.ipdl b/ipc/ipdl/test/ipdl/ok/race_MultiOut.ipdl
index 6925f53ef4c..80cffd91c1f 100644
--- a/ipc/ipdl/test/ipdl/ok/race_MultiOut.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/race_MultiOut.ipdl
@@ -1,10 +1,10 @@
 protocol race_MultiOut {
 child:
-    Msg1();
-    Msg1_();
+    async Msg1();
+    async Msg1_();
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
 start state S15:
     send Msg1 goto S16 or S17;
diff --git a/ipc/ipdl/test/ipdl/ok/race_Stateless.ipdl b/ipc/ipdl/test/ipdl/ok/race_Stateless.ipdl
index 4d757c92458..6cffe1e7c43 100644
--- a/ipc/ipdl/test/ipdl/ok/race_Stateless.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/race_Stateless.ipdl
@@ -2,11 +2,11 @@ protocol race_Stateless {
 //    manages Child;
 
 child:
-    Msg1();
-    Msg1_();
+    async Msg1();
+    async Msg1_();
 parent:
-    Msg2();
-    Msg2_();
+    async Msg2();
+    async Msg2_();
 
 
     // OK: this is trivial stateless protocol, so race-free "by definition"
diff --git a/ipc/ipdl/test/ipdl/ok/selfRecUnion.ipdl b/ipc/ipdl/test/ipdl/ok/selfRecUnion.ipdl
index 3c49048f52d..70f04602c01 100644
--- a/ipc/ipdl/test/ipdl/ok/selfRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/selfRecUnion.ipdl
@@ -6,6 +6,6 @@ union R {
 
 protocol selfRecUnion {
 child:
-    Test(R r);
-    __delete__();
+    async Test(R r);
+    async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/shmem.ipdl b/ipc/ipdl/test/ipdl/ok/shmem.ipdl
index f8ce9fee03a..8bc44010b96 100644
--- a/ipc/ipdl/test/ipdl/ok/shmem.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/shmem.ipdl
@@ -5,7 +5,7 @@ union Foo {
 
 intr protocol shmem {
 parent:
-    Msg(Shmem s, Foo f);
+    async Msg(Shmem s, Foo f);
     sync SyncMsg(Shmem s, Foo f)
         returns (Shmem t, Foo g);
     intr InterruptMsg(Shmem s, Foo f)
diff --git a/ipc/ipdl/test/ipdl/ok/syncProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/syncProtocol.ipdl
index a064cdf54dc..cfe7760e630 100644
--- a/ipc/ipdl/test/ipdl/ok/syncProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/syncProtocol.ipdl
@@ -3,7 +3,7 @@ sync protocol syncProtocol {
     // sanity check of sync protocols
 
 child:
-    AsyncMsg();
+    async AsyncMsg();
 
 parent:
     sync SyncMsg() returns (int i);
diff --git a/ipc/ipdl/test/ipdl/ok/threeDirections.ipdl b/ipc/ipdl/test/ipdl/ok/threeDirections.ipdl
index 40c418aeb43..c06f9d56f08 100644
--- a/ipc/ipdl/test/ipdl/ok/threeDirections.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/threeDirections.ipdl
@@ -2,12 +2,12 @@ protocol threeDirections {
 
     // sanity check that the three direction specifiers are being accepted
 child:
-    ChildMsg();
+    async ChildMsg();
 
 parent:
-    ParentMsg();
+    async ParentMsg();
 
 both:
-    BothMsg();
+    async BothMsg();
 
 };
diff --git a/ipc/ipdl/test/ipdl/ok/union_Namespaced.ipdl b/ipc/ipdl/test/ipdl/ok/union_Namespaced.ipdl
index 0bf345771cf..02f86f9ded8 100644
--- a/ipc/ipdl/test/ipdl/ok/union_Namespaced.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/union_Namespaced.ipdl
@@ -12,7 +12,7 @@ namespace puppies {
 
 protocol union_Namespaced {
 child:
-    Msg(Socks s);
+    async Msg(Socks s);
 };
 
 } // namespace puppies
diff --git a/ipc/testshell/PTestShell.ipdl b/ipc/testshell/PTestShell.ipdl
index 26ed4fe74d1..db4d7eedcb5 100644
--- a/ipc/testshell/PTestShell.ipdl
+++ b/ipc/testshell/PTestShell.ipdl
@@ -16,11 +16,11 @@ async protocol PTestShell
   manages PTestShellCommand;
 
 child:
-  __delete__();
+  async __delete__();
 
-  ExecuteCommand(nsString aCommand);
+  async ExecuteCommand(nsString aCommand);
 
-  PTestShellCommand(nsString aCommand);
+  async PTestShellCommand(nsString aCommand);
 };
 
 } // namespace ipc
diff --git a/ipc/testshell/PTestShellCommand.ipdl b/ipc/testshell/PTestShellCommand.ipdl
index 47bef5db793..fb6efd99fd3 100644
--- a/ipc/testshell/PTestShellCommand.ipdl
+++ b/ipc/testshell/PTestShellCommand.ipdl
@@ -13,7 +13,7 @@ protocol PTestShellCommand
   manager PTestShell;
 
 parent:
-  __delete__(nsString aResponse);
+  async __delete__(nsString aResponse);
 };
 
 } // namespace ipc
diff --git a/netwerk/cookie/PCookieService.ipdl b/netwerk/cookie/PCookieService.ipdl
index 183a4ff3f9c..414b4911309 100644
--- a/netwerk/cookie/PCookieService.ipdl
+++ b/netwerk/cookie/PCookieService.ipdl
@@ -102,7 +102,7 @@ parent:
                                      bool fromHttp,
                                      SerializedLoadContext loadContext);
 
-  __delete__();
+  async __delete__();
 };
 
 }
diff --git a/netwerk/dns/PDNSRequest.ipdl b/netwerk/dns/PDNSRequest.ipdl
index 42094054546..2288ab09e59 100644
--- a/netwerk/dns/PDNSRequest.ipdl
+++ b/netwerk/dns/PDNSRequest.ipdl
@@ -23,12 +23,12 @@ parent:
 
   // Pass args here rather than storing them in the parent; they are only
   // needed if the request is to be canceled.
-  CancelDNSRequest(nsCString hostName, uint32_t flags,
-                   nsCString networkInterface, nsresult reason);
-   __delete__();
+  async CancelDNSRequest(nsCString hostName, uint32_t flags,
+                         nsCString networkInterface, nsresult reason);
+  async __delete__();
 
 child:
-  LookupCompleted(DNSRequestResponse reply);
+  async LookupCompleted(DNSRequestResponse reply);
 
 };
 
diff --git a/netwerk/ipc/PChannelDiverter.ipdl b/netwerk/ipc/PChannelDiverter.ipdl
index dd7aa85d94c..12be1f09b42 100644
--- a/netwerk/ipc/PChannelDiverter.ipdl
+++ b/netwerk/ipc/PChannelDiverter.ipdl
@@ -18,7 +18,7 @@ async protocol PChannelDiverter
   manager PNecko;
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 }// namespace net
diff --git a/netwerk/ipc/PDataChannel.ipdl b/netwerk/ipc/PDataChannel.ipdl
index 17a340cc0d4..69eef43aed4 100644
--- a/netwerk/ipc/PDataChannel.ipdl
+++ b/netwerk/ipc/PDataChannel.ipdl
@@ -18,7 +18,7 @@ async protocol PDataChannel
 parent:
   // Note: channels are opened during construction, so no open method here:
   // see PNecko.ipdl
-  __delete__();
+  async __delete__();
 };
 
 } // namespace net
diff --git a/netwerk/ipc/PNecko.ipdl b/netwerk/ipc/PNecko.ipdl
index 2e1f2f51829..c3befb0fee2 100644
--- a/netwerk/ipc/PNecko.ipdl
+++ b/netwerk/ipc/PNecko.ipdl
@@ -58,61 +58,61 @@ prio(normal upto urgent) sync protocol PNecko
   manages PChannelDiverter;
 
 parent:
-  __delete__();
+  async __delete__();
 
   prio(urgent) async PCookieService();
-  PHttpChannel(PBrowserOrId browser,
-               SerializedLoadContext loadContext,
-               HttpChannelCreationArgs args);
-  PWyciwygChannel();
-  PFTPChannel(PBrowserOrId browser, SerializedLoadContext loadContext,
-              FTPChannelCreationArgs args);
+  async PHttpChannel(PBrowserOrId browser,
+                     SerializedLoadContext loadContext,
+                     HttpChannelCreationArgs args);
+  async PWyciwygChannel();
+  async PFTPChannel(PBrowserOrId browser, SerializedLoadContext loadContext,
+                    FTPChannelCreationArgs args);
 
-  PWebSocket(PBrowserOrId browser, SerializedLoadContext loadContext,
-             uint32_t aSerialID);
-  PTCPServerSocket(uint16_t localPort, uint16_t backlog, bool useArrayBuffers);
-  PUDPSocket(Principal principal, nsCString filter);
+  async PWebSocket(PBrowserOrId browser, SerializedLoadContext loadContext,
+                   uint32_t aSerialID);
+  async PTCPServerSocket(uint16_t localPort, uint16_t backlog, bool useArrayBuffers);
+  async PUDPSocket(Principal principal, nsCString filter);
 
-  PDNSRequest(nsCString hostName, uint32_t flags, nsCString networkInterface);
+  async PDNSRequest(nsCString hostName, uint32_t flags, nsCString networkInterface);
 
-  PWebSocketEventListener(uint64_t aInnerWindowID);
+  async PWebSocketEventListener(uint64_t aInnerWindowID);
 
   /* Predictor Methods */
-  PredPredict(OptionalURIParams targetURI, OptionalURIParams sourceURI,
-              uint32_t reason, SerializedLoadContext loadContext,
-              bool hasVerifier);
-  PredLearn(URIParams targetURI, OptionalURIParams sourceURI,
-            uint32_t reason, SerializedLoadContext loadContext);
-  PredReset();
+  async PredPredict(OptionalURIParams targetURI, OptionalURIParams sourceURI,
+                    uint32_t reason, SerializedLoadContext loadContext,
+                    bool hasVerifier);
+  async PredLearn(URIParams targetURI, OptionalURIParams sourceURI,
+                  uint32_t reason, SerializedLoadContext loadContext);
+  async PredReset();
 
-  PRemoteOpenFile(SerializedLoadContext loadContext,
-                  URIParams fileuri,
-                  OptionalURIParams appuri);
+  async PRemoteOpenFile(SerializedLoadContext loadContext,
+                        URIParams fileuri,
+                        OptionalURIParams appuri);
 
-  SpeculativeConnect(URIParams uri, bool anonymous);
-  HTMLDNSPrefetch(nsString hostname, uint16_t flags);
-  CancelHTMLDNSPrefetch(nsString hostname, uint16_t flags, nsresult reason);
+  async SpeculativeConnect(URIParams uri, bool anonymous);
+  async HTMLDNSPrefetch(nsString hostname, uint16_t flags);
+  async CancelHTMLDNSPrefetch(nsString hostname, uint16_t flags, nsresult reason);
 
   /**
    * channelId is used to establish a connection between redirect channels in
    * the parent and the child when we're redirecting to a data: URI.
    */
-  PDataChannel(uint32_t channelId);
+  async PDataChannel(uint32_t channelId);
 
-  PRtspController();
-  PRtspChannel(RtspChannelConnectArgs args);
-  PChannelDiverter(ChannelDiverterArgs channel);
+  async PRtspController();
+  async PRtspChannel(RtspChannelConnectArgs args);
+  async PChannelDiverter(ChannelDiverterArgs channel);
 
   /**
    * These are called from the child with the results of the auth prompt.
    * callbackId is the id that was passed in PBrowser::AsyncAuthPrompt,
    * corresponding to an nsIAuthPromptCallback
    */
-  OnAuthAvailable(uint64_t callbackId, nsString user,
-                  nsString password, nsString domain);
-  OnAuthCancelled(uint64_t callbackId, bool userCancel);
+  async OnAuthAvailable(uint64_t callbackId, nsString user,
+                        nsString password, nsString domain);
+  async OnAuthCancelled(uint64_t callbackId, bool userCancel);
 
-  RemoveSchedulingContext(nsCString scid);
+  async RemoveSchedulingContext(nsCString scid);
 
 child:
   /*
@@ -120,20 +120,20 @@ child:
    * NestedFrameId is the id corresponding to the PBrowser.  It is the same id
    * that was passed to the PBrowserOrId param in to the PHttpChannel constructor
    */
-  AsyncAuthPromptForNestedFrame(TabId nestedFrameId, nsCString uri,
-                                nsString realm, uint64_t callbackId);
+  async AsyncAuthPromptForNestedFrame(TabId nestedFrameId, nsCString uri,
+                                      nsString realm, uint64_t callbackId);
   // Notifies child that a given app is now offline (or online)
-  AppOfflineStatus(uint32_t appId, bool offline);
+  async AppOfflineStatus(uint32_t appId, bool offline);
 
   /* Predictor Methods */
-  PredOnPredictPreconnect(URIParams uri);
-  PredOnPredictDNS(URIParams uri);
+  async PredOnPredictPreconnect(URIParams uri);
+  async PredOnPredictDNS(URIParams uri);
 
 both:
   // Actually we need PTCPSocket() for parent. But ipdl disallows us having different
   // signatures on parent and child. So when constructing the parent side object, we just 
   // leave host/port unused.
-  PTCPSocket(nsString host, uint16_t port);
+  async PTCPSocket(nsString host, uint16_t port);
 };
 
 
diff --git a/netwerk/ipc/PRemoteOpenFile.ipdl b/netwerk/ipc/PRemoteOpenFile.ipdl
index d09c9d37c9c..0498d6f87d7 100644
--- a/netwerk/ipc/PRemoteOpenFile.ipdl
+++ b/netwerk/ipc/PRemoteOpenFile.ipdl
@@ -20,7 +20,7 @@ protocol PRemoteOpenFile
 
 child:
   // Your file handle is ready, Sir...
-  __delete__(FileDescriptor fd);
+  async __delete__(FileDescriptor fd);
 };
 
 
diff --git a/netwerk/ipc/PRtspChannel.ipdl b/netwerk/ipc/PRtspChannel.ipdl
index c8a4bbe1a1a..e884cae7620 100644
--- a/netwerk/ipc/PRtspChannel.ipdl
+++ b/netwerk/ipc/PRtspChannel.ipdl
@@ -18,7 +18,7 @@ async protocol PRtspChannel
 parent:
   // Note: channels are opened during construction, so no open method here:
   // see PNecko.ipdl
-  __delete__();
+  async __delete__();
 };
 
 } // namespace net
diff --git a/netwerk/ipc/PRtspController.ipdl b/netwerk/ipc/PRtspController.ipdl
index de74461779f..656dbe0b9a5 100644
--- a/netwerk/ipc/PRtspController.ipdl
+++ b/netwerk/ipc/PRtspController.ipdl
@@ -37,27 +37,27 @@ async protocol PRtspController
   manager PNecko;
 
 parent:
-  AsyncOpen(URIParams aURI);
-  Play();
-  Pause();
-  Resume();
-  Suspend();
-  Seek(uint64_t offset);
-  Stop();
-  PlaybackEnded();
-  __delete__();
+  async AsyncOpen(URIParams aURI);
+  async Play();
+  async Pause();
+  async Resume();
+  async Suspend();
+  async Seek(uint64_t offset);
+  async Stop();
+  async PlaybackEnded();
+  async __delete__();
 
 child:
-  OnMediaDataAvailable(uint8_t index,
-                       nsCString data,
-                       uint32_t length,
-                       uint32_t offset,
-                       RtspMetadataParam[] meta);
-  OnConnected(uint8_t index,
-              RtspMetadataParam[] meta);
-  OnDisconnected(uint8_t index,
-                 nsresult reason);
-  AsyncOpenFailed(nsresult reason);
+  async OnMediaDataAvailable(uint8_t index,
+                             nsCString data,
+                             uint32_t length,
+                             uint32_t offset,
+                             RtspMetadataParam[] meta);
+  async OnConnected(uint8_t index,
+                    RtspMetadataParam[] meta);
+  async OnDisconnected(uint8_t index,
+                       nsresult reason);
+  async AsyncOpenFailed(nsresult reason);
 };
 
 } //namespace net
diff --git a/netwerk/protocol/ftp/PFTPChannel.ipdl b/netwerk/protocol/ftp/PFTPChannel.ipdl
index b6b0458896f..9793074f6d5 100644
--- a/netwerk/protocol/ftp/PFTPChannel.ipdl
+++ b/netwerk/protocol/ftp/PFTPChannel.ipdl
@@ -26,45 +26,45 @@ parent:
   // Note: channels are opened during construction, so no open method here:
   // see PNecko.ipdl
 
-  __delete__();
+  async __delete__();
 
-  Cancel(nsresult status);
-  Suspend();
-  Resume();
+  async Cancel(nsresult status);
+  async Suspend();
+  async Resume();
 
   // Divert OnDataAvailable to the parent.
-  DivertOnDataAvailable(nsCString data,
-                        uint64_t  offset,
-                        uint32_t  count);
+  async DivertOnDataAvailable(nsCString data,
+                              uint64_t  offset,
+                              uint32_t  count);
 
   // Divert OnStopRequest to the parent.
-  DivertOnStopRequest(nsresult statusCode);
+  async DivertOnStopRequest(nsresult statusCode);
 
   // Child has no more events/messages to divert to the parent.
-  DivertComplete();
+  async DivertComplete();
 
 child:
-  OnStartRequest(nsresult aChannelStatus,
-                 int64_t aContentLength,
-                 nsCString aContentType,
-                 PRTime aLastModified,
-                 nsCString aEntityID,
-                 URIParams aURI);
-  OnDataAvailable(nsresult channelStatus,
-                  nsCString data,
-                  uint64_t offset,
-                  uint32_t count);
-  OnStopRequest(nsresult channelStatus);
-  FailedAsyncOpen(nsresult statusCode);
+  async OnStartRequest(nsresult aChannelStatus,
+                       int64_t aContentLength,
+                       nsCString aContentType,
+                       PRTime aLastModified,
+                       nsCString aEntityID,
+                       URIParams aURI);
+  async OnDataAvailable(nsresult channelStatus,
+                        nsCString data,
+                        uint64_t offset,
+                        uint32_t count);
+  async OnStopRequest(nsresult channelStatus);
+  async FailedAsyncOpen(nsresult statusCode);
 
   // Parent has been suspended for diversion; no more events to be enqueued.
-  FlushedForDiversion();
+  async FlushedForDiversion();
 
   // Child should resume processing the ChannelEventQueue, i.e. diverting any
   // OnDataAvailable and OnStopRequest messages in the queue back to the parent.
-  DivertMessages();
+  async DivertMessages();
 
-  DeleteSelf();
+  async DeleteSelf();
 };
 
 } // namespace net
diff --git a/netwerk/protocol/http/PHttpChannel.ipdl b/netwerk/protocol/http/PHttpChannel.ipdl
index 0002376bd41..18f93f61fcc 100644
--- a/netwerk/protocol/http/PHttpChannel.ipdl
+++ b/netwerk/protocol/http/PHttpChannel.ipdl
@@ -31,27 +31,27 @@ parent:
   // Note: channels are opened during construction, so no open method here:
   // see PNecko.ipdl
 
-  SetPriority(uint16_t priority);
-  SetClassOfService(uint32_t cos);
+  async SetPriority(uint16_t priority);
+  async SetClassOfService(uint32_t cos);
 
-  SetCacheTokenCachedCharset(nsCString charset);
+  async SetCacheTokenCachedCharset(nsCString charset);
 
-  UpdateAssociatedContentSecurity(int32_t broken,
-                                  int32_t no);
-  Suspend();
-  Resume();
+  async UpdateAssociatedContentSecurity(int32_t broken,
+                                        int32_t no);
+  async Suspend();
+  async Resume();
 
-  Cancel(nsresult status);
+  async Cancel(nsresult status);
 
   // Reports approval/veto of redirect by child process redirect observers
-  Redirect2Verify(nsresult result, RequestHeaderTuples changedHeaders,
-                  uint32_t loadFlags, OptionalURIParams apiRedirectTo,
-                  OptionalCorsPreflightArgs corsPreflightArgs);
+  async Redirect2Verify(nsresult result, RequestHeaderTuples changedHeaders,
+                        uint32_t loadFlags, OptionalURIParams apiRedirectTo,
+                        OptionalCorsPreflightArgs corsPreflightArgs);
 
   // For document loads we keep this protocol open after child's
   // OnStopRequest, and send this msg (instead of __delete__) to allow
   // partial cleanup on parent.
-  DocumentChannelCleanup();
+  async DocumentChannelCleanup();
 
   // This might have to be sync. If this fails we must fail the document load
   // to avoid endless loop.
@@ -66,96 +66,96 @@ parent:
   // we reload the document to take the effect. If we fail to mark the entry
   // as foreign, we will end up in the same situation and reload again and
   // again, indefinitely.
-  MarkOfflineCacheEntryAsForeign();
+  async MarkOfflineCacheEntryAsForeign();
 
   // Divert OnDataAvailable to the parent.
-  DivertOnDataAvailable(nsCString data,
-                        uint64_t  offset,
-                        uint32_t  count);
+  async DivertOnDataAvailable(nsCString data,
+                              uint64_t  offset,
+                              uint32_t  count);
 
   // Divert OnStopRequest to the parent.
-  DivertOnStopRequest(nsresult statusCode);
+  async DivertOnStopRequest(nsresult statusCode);
 
   // Child has no more events/messages to divert to the parent.
-  DivertComplete();
+  async DivertComplete();
 
   // Child has detected a CORS check failure, so needs to tell the parent
   // to remove any matching entry from the CORS preflight cache.
-  RemoveCorsPreflightCacheEntry(URIParams uri,
-                                PrincipalInfo requestingPrincipal);
+  async RemoveCorsPreflightCacheEntry(URIParams uri,
+                                      PrincipalInfo requestingPrincipal);
 
-  __delete__();
+  async __delete__();
 
 child:
-  OnStartRequest(nsresult            channelStatus,
-                 nsHttpResponseHead  responseHead,
-                 bool                useResponseHead,
-                 nsHttpHeaderArray   requestHeaders,
-                 bool                isFromCache,
-                 bool                cacheEntryAvailable,
-                 uint32_t            cacheExpirationTime,
-                 nsCString           cachedCharset,
-                 nsCString           securityInfoSerialization,
-                 NetAddr             selfAddr,
-                 NetAddr             peerAddr,
-                 int16_t             redirectCount,
-                 uint32_t            cacheKey);
+  async OnStartRequest(nsresult            channelStatus,
+                       nsHttpResponseHead  responseHead,
+                       bool                useResponseHead,
+                       nsHttpHeaderArray   requestHeaders,
+                       bool                isFromCache,
+                       bool                cacheEntryAvailable,
+                       uint32_t            cacheExpirationTime,
+                       nsCString           cachedCharset,
+                       nsCString           securityInfoSerialization,
+                       NetAddr             selfAddr,
+                       NetAddr             peerAddr,
+                       int16_t             redirectCount,
+                       uint32_t            cacheKey);
 
   // Combines a single OnDataAvailable and its associated OnProgress &
   // OnStatus calls into one IPDL message
-  OnTransportAndData(nsresult  channelStatus,
-                     nsresult  transportStatus,
-                     uint64_t  progress,
-                     uint64_t  progressMax,
-                     nsCString data,
-                     uint64_t  offset,
-                     uint32_t  count);
+  async OnTransportAndData(nsresult  channelStatus,
+                           nsresult  transportStatus,
+                           uint64_t  progress,
+                           uint64_t  progressMax,
+                           nsCString data,
+                           uint64_t  offset,
+                           uint32_t  count);
 
-  OnStopRequest(nsresult channelStatus, ResourceTimingStruct timing);
+  async OnStopRequest(nsresult channelStatus, ResourceTimingStruct timing);
 
-  OnProgress(int64_t progress, int64_t progressMax);
+  async OnProgress(int64_t progress, int64_t progressMax);
 
-  OnStatus(nsresult status);
+  async OnStatus(nsresult status);
 
   // Used to cancel child channel if we hit errors during creating and
   // AsyncOpen of nsHttpChannel on the parent.
-  FailedAsyncOpen(nsresult status);
+  async FailedAsyncOpen(nsresult status);
 
   // Called to initiate content channel redirect, starts talking to sinks
   // on the content process and reports result via Redirect2Verify above
-  Redirect1Begin(uint32_t           newChannelId,
-                 URIParams          newUri,
-                 uint32_t           redirectFlags,
-                 nsHttpResponseHead responseHead,
-                 nsCString          securityInfoSerialization);
+  async Redirect1Begin(uint32_t           newChannelId,
+                       URIParams          newUri,
+                       uint32_t           redirectFlags,
+                       nsHttpResponseHead responseHead,
+                       nsCString          securityInfoSerialization);
 
   // Called if redirect successful so that child can complete setup.
-  Redirect3Complete();
+  async Redirect3Complete();
 
   // Associate the child with an application ids
-  AssociateApplicationCache(nsCString groupID,
-                            nsCString clientID);
+  async AssociateApplicationCache(nsCString groupID,
+                                  nsCString clientID);
 
   // Tell the child that tracking protection was disabled for this load.
-  NotifyTrackingProtectionDisabled();
+  async NotifyTrackingProtectionDisabled();
 
   // Parent has been suspended for diversion; no more events to be enqueued.
-  FlushedForDiversion();
+  async FlushedForDiversion();
 
   // Child should resume processing the ChannelEventQueue, i.e. diverting any
   // OnDataAvailable and OnStopRequest messages in the queue back to the parent.
-  DivertMessages();
+  async DivertMessages();
 
   // Report a security message to the console associated with this
   // channel.
-  ReportSecurityMessage(nsString messageTag, nsString messageCategory);
+  async ReportSecurityMessage(nsString messageTag, nsString messageCategory);
 
   // Tell child to delete channel (all IPDL deletes must be done from child to
   // avoid races: see bug 591708).
-  DeleteSelf();
+  async DeleteSelf();
 
   // Tell the child to issue a deprecation warning.
-  IssueDeprecationWarning(uint32_t warning, bool asError);
+  async IssueDeprecationWarning(uint32_t warning, bool asError);
 };
 
 
diff --git a/netwerk/protocol/websocket/PWebSocket.ipdl b/netwerk/protocol/websocket/PWebSocket.ipdl
index 82a451b1a13..42eaa74881e 100644
--- a/netwerk/protocol/websocket/PWebSocket.ipdl
+++ b/netwerk/protocol/websocket/PWebSocket.ipdl
@@ -24,35 +24,35 @@ async protocol PWebSocket
 
 parent:
   // Forwarded methods corresponding to methods on nsIWebSocketChannel
-  AsyncOpen(URIParams aURI,
-            nsCString aOrigin,
-            uint64_t aInnerWindowID,
-            nsCString aProtocol,
-            bool aSecure,
-            // ping values only meaningful if client set them
-            uint32_t aPingInterval,
-            bool aClientSetPingInterval,
-            uint32_t aPingTimeout,
-            bool aClientSetPingTimeout,
-            OptionalLoadInfoArgs aLoadInfoArgs);
-  Close(uint16_t code, nsCString reason);
-  SendMsg(nsCString aMsg);
-  SendBinaryMsg(nsCString aMsg);
-  SendBinaryStream(InputStreamParams aStream, uint32_t aLength);
+  async AsyncOpen(URIParams aURI,
+                  nsCString aOrigin,
+                  uint64_t aInnerWindowID,
+                  nsCString aProtocol,
+                  bool aSecure,
+                  // ping values only meaningful if client set them
+                  uint32_t aPingInterval,
+                  bool aClientSetPingInterval,
+                  uint32_t aPingTimeout,
+                  bool aClientSetPingTimeout,
+                  OptionalLoadInfoArgs aLoadInfoArgs);
+  async Close(uint16_t code, nsCString reason);
+  async SendMsg(nsCString aMsg);
+  async SendBinaryMsg(nsCString aMsg);
+  async SendBinaryStream(InputStreamParams aStream, uint32_t aLength);
 
-  DeleteSelf();
+  async DeleteSelf();
 
 child:
   // Forwarded notifications corresponding to the nsIWebSocketListener interface
-  OnStart(nsCString aProtocol, nsCString aExtensions,
-          nsString aEffectiveURL, bool aEncrypted);
-  OnStop(nsresult aStatusCode);
-  OnMessageAvailable(nsCString aMsg);
-  OnBinaryMessageAvailable(nsCString aMsg);
-  OnAcknowledge(uint32_t aSize);
-  OnServerClose(uint16_t code, nsCString aReason);
+  async OnStart(nsCString aProtocol, nsCString aExtensions,
+                nsString aEffectiveURL, bool aEncrypted);
+  async OnStop(nsresult aStatusCode);
+  async OnMessageAvailable(nsCString aMsg);
+  async OnBinaryMessageAvailable(nsCString aMsg);
+  async OnAcknowledge(uint32_t aSize);
+  async OnServerClose(uint16_t code, nsCString aReason);
 
-  __delete__();
+  async __delete__();
 
 };
 
diff --git a/netwerk/protocol/websocket/PWebSocketEventListener.ipdl b/netwerk/protocol/websocket/PWebSocketEventListener.ipdl
index ef0310d7cb7..35a10745787 100644
--- a/netwerk/protocol/websocket/PWebSocketEventListener.ipdl
+++ b/netwerk/protocol/websocket/PWebSocketEventListener.ipdl
@@ -17,34 +17,34 @@ async protocol PWebSocketEventListener
   manager PNecko;
 
 child:
-  WebSocketCreated(uint32_t awebSocketSerialID,
-                   nsString aURI,
-                   nsCString aProtocols);
+  async WebSocketCreated(uint32_t awebSocketSerialID,
+                         nsString aURI,
+                         nsCString aProtocols);
 
-  WebSocketOpened(uint32_t awebSocketSerialID,
-                  nsString aEffectiveURI,
-                  nsCString aProtocols,
-                  nsCString aExtensions);
+  async WebSocketOpened(uint32_t awebSocketSerialID,
+                        nsString aEffectiveURI,
+                        nsCString aProtocols,
+                        nsCString aExtensions);
 
-  WebSocketMessageAvailable(uint32_t awebSocketSerialID,
-                            nsCString aData,
-                            uint16_t aMessageType);
+  async WebSocketMessageAvailable(uint32_t awebSocketSerialID,
+                                  nsCString aData,
+                                  uint16_t aMessageType);
 
-  WebSocketClosed(uint32_t awebSocketSerialID,
-                  bool aWasClean,
-                  uint16_t aCode,
-                  nsString aReason);
+  async WebSocketClosed(uint32_t awebSocketSerialID,
+                        bool aWasClean,
+                        uint16_t aCode,
+                        nsString aReason);
 
-  FrameReceived(uint32_t aWebSocketSerialID,
-                WebSocketFrameData aFrameData);
+  async FrameReceived(uint32_t aWebSocketSerialID,
+                      WebSocketFrameData aFrameData);
 
-  FrameSent(uint32_t aWebSocketSerialID,
-            WebSocketFrameData aFrameData);
+  async FrameSent(uint32_t aWebSocketSerialID,
+                  WebSocketFrameData aFrameData);
 
-  __delete__();
+  async __delete__();
 
 parent:
-  Close();
+  async Close();
 };
 
 } //namespace net
diff --git a/netwerk/protocol/wyciwyg/PWyciwygChannel.ipdl b/netwerk/protocol/wyciwyg/PWyciwygChannel.ipdl
index 092ed1e8049..c3d21c1743a 100644
--- a/netwerk/protocol/wyciwyg/PWyciwygChannel.ipdl
+++ b/netwerk/protocol/wyciwyg/PWyciwygChannel.ipdl
@@ -1,3 +1,5 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et tw=80 ft=cpp : */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
@@ -19,39 +21,39 @@ protocol PWyciwygChannel
   manager PNecko;
 
 parent:
-  __delete__();
+  async __delete__();
 
-  Init(URIParams     uri,
-       PrincipalInfo requestingPrincipalInfo,
-       PrincipalInfo triggeringPrincipalInfo,
-       uint32_t      securityFlags,
-       uint32_t      contentPolicyType);
-  AsyncOpen(URIParams             originalURI,
-            uint32_t              loadFlags,
-            SerializedLoadContext loadContext,
-            PBrowserOrId browser);
-  AppData(SerializedLoadContext loadContext, PBrowserOrId browser);
+  async Init(URIParams     uri,
+             PrincipalInfo requestingPrincipalInfo,
+             PrincipalInfo triggeringPrincipalInfo,
+             uint32_t      securityFlags,
+             uint32_t      contentPolicyType);
+  async AsyncOpen(URIParams             originalURI,
+                  uint32_t              loadFlags,
+                  SerializedLoadContext loadContext,
+                  PBrowserOrId browser);
+  async AppData(SerializedLoadContext loadContext, PBrowserOrId browser);
 
   // methods corresponding to those of nsIWyciwygChannel
-  WriteToCacheEntry(nsString data);
-  CloseCacheEntry(nsresult reason);
-  SetCharsetAndSource(int32_t source, nsCString charset);
-  SetSecurityInfo(nsCString securityInfo);
-  Cancel(nsresult status);
+  async WriteToCacheEntry(nsString data);
+  async CloseCacheEntry(nsresult reason);
+  async SetCharsetAndSource(int32_t source, nsCString charset);
+  async SetSecurityInfo(nsCString securityInfo);
+  async Cancel(nsresult status);
 
 child:
-  OnStartRequest(nsresult  statusCode,
-                 int64_t   contentLength,
-                 int32_t   source,
-                 nsCString charset,
-                 nsCString securityInfo);
+  async OnStartRequest(nsresult  statusCode,
+                       int64_t   contentLength,
+                       int32_t   source,
+                       nsCString charset,
+                       nsCString securityInfo);
 
-  OnDataAvailable(nsCString data,
-                  uint64_t  offset);
+  async OnDataAvailable(nsCString data,
+                        uint64_t  offset);
 
-  OnStopRequest(nsresult statusCode);
+  async OnStopRequest(nsresult statusCode);
 
-  CancelEarly(nsresult statusCode);
+  async CancelEarly(nsresult statusCode);
 };
 
 
diff --git a/security/manager/ssl/PPSMContentDownloader.ipdl b/security/manager/ssl/PPSMContentDownloader.ipdl
index ac97d7c444f..a9c0fc266e9 100644
--- a/security/manager/ssl/PPSMContentDownloader.ipdl
+++ b/security/manager/ssl/PPSMContentDownloader.ipdl
@@ -14,14 +14,14 @@ protocol PPSMContentDownloader
   manager PContent;
 
 parent:
-  OnStartRequest(uint32_t contentLength);
-  OnDataAvailable(nsCString data, uint64_t offset, uint32_t count);
-  OnStopRequest(nsresult code);
+  async OnStartRequest(uint32_t contentLength);
+  async OnDataAvailable(nsCString data, uint64_t offset, uint32_t count);
+  async OnStopRequest(nsresult code);
 
-  DivertToParentUsing(PChannelDiverter diverter);
+  async DivertToParentUsing(PChannelDiverter diverter);
 
 child:
-  __delete__();
+  async __delete__();
 };
 
 } // namespace psm
diff --git a/uriloader/exthandler/PExternalHelperApp.ipdl b/uriloader/exthandler/PExternalHelperApp.ipdl
index 914b7cc2ddd..c7d526c19d1 100644
--- a/uriloader/exthandler/PExternalHelperApp.ipdl
+++ b/uriloader/exthandler/PExternalHelperApp.ipdl
@@ -13,15 +13,15 @@ protocol PExternalHelperApp
   manager PContent;
 
 parent:
-  OnStartRequest(nsCString entityID);
-  OnDataAvailable(nsCString data, uint64_t offset, uint32_t count);
-  OnStopRequest(nsresult code);
+  async OnStartRequest(nsCString entityID);
+  async OnDataAvailable(nsCString data, uint64_t offset, uint32_t count);
+  async OnStopRequest(nsresult code);
 
-  DivertToParentUsing(PChannelDiverter diverter);
+  async DivertToParentUsing(PChannelDiverter diverter);
 
 child:
-  Cancel(nsresult aStatus);
-  __delete__();
+  async Cancel(nsresult aStatus);
+  async __delete__();
 };
 
 
diff --git a/uriloader/exthandler/PHandlerService.ipdl b/uriloader/exthandler/PHandlerService.ipdl
index 7e5cff0faac..bcaab60ac3c 100644
--- a/uriloader/exthandler/PHandlerService.ipdl
+++ b/uriloader/exthandler/PHandlerService.ipdl
@@ -34,7 +34,7 @@ parent:
       returns (bool exists);
   sync GetTypeFromExtension(nsCString aFileExtension)
       returns (nsCString type);
-  __delete__();
+  async __delete__();
 };
 
 
diff --git a/uriloader/prefetch/POfflineCacheUpdate.ipdl b/uriloader/prefetch/POfflineCacheUpdate.ipdl
index d063ac2b0a5..e6247525227 100644
--- a/uriloader/prefetch/POfflineCacheUpdate.ipdl
+++ b/uriloader/prefetch/POfflineCacheUpdate.ipdl
@@ -16,12 +16,12 @@ protocol POfflineCacheUpdate
   manager PContent;
 
 parent:
-  __delete__();
+  async __delete__();
 
 child:
-  NotifyStateEvent(uint32_t stateEvent, uint64_t byteProgress);
-  AssociateDocuments(nsCString cacheGroupId, nsCString cacheClientId);
-  Finish(bool succeeded, bool isUpgrade);
+  async NotifyStateEvent(uint32_t stateEvent, uint64_t byteProgress);
+  async AssociateDocuments(nsCString cacheGroupId, nsCString cacheClientId);
+  async Finish(bool succeeded, bool isUpgrade);
 };
 
 }