Bug 1103036 - Follow-up to initial patch; r=jchen

dom/ipc/ContentChild.cpp

@@ -2496,11 +2496,10 @@ ContentChild::RecvShutdown()
     if (os) {
         os->NotifyObservers(this, "content-child-shutdown", nullptr);
     }
-    // Let the parent know we're done and let it close the channel.
-    // Both sides will clean up even if an error occurs here.
-    MessageLoop::current()->PostTask(
-        FROM_HERE,
-        NewRunnableMethod(this, &ContentChild::SendFinishShutdown));
+
+    // Ignore errors here. If this fails, the parent will kill us after a
+    // timeout.
+    unused << SendFinishShutdown();
     return true;
 }
 

dom/ipc/ContentParent.cpp

@@ -1502,8 +1502,7 @@ ContentParent::ShutDownProcess(ShutDownMethod aMethod)
     // other methods. We first call Shutdown() in the child. After the child is
     // ready, it calls FinishShutdown() on us. Then we close the channel.
     if (aMethod == SEND_SHUTDOWN_MESSAGE) {
-
-        if (SendShutdown()) {
+        if (mIPCOpen && SendShutdown()) {
             mShutdownPending = true;
         }
 
@@ -1776,7 +1775,7 @@ ContentParent::ActorDestroy(ActorDestroyReason why)
 
     // Signal shutdown completion regardless of error state,
     // so we can finish waiting in the xpcom-shutdown observer.
-    mShutdownComplete = true;
+    mIPCOpen = false;
 
     if (why == NormalShutdown && !mCalledClose) {
         // If we shut down normally but haven't called Close, assume somebody
@@ -2000,7 +1999,7 @@ ContentParent::InitializeMembers()
     mCalledKillHard = false;
     mCreatedPairedMinidumps = false;
     mShutdownPending = false;
-    mShutdownComplete = false;
+    mIPCOpen = true;
 }
 
 ContentParent::ContentParent(mozIApplication* aApp,
@@ -2745,15 +2744,15 @@ ContentParent::Observe(nsISupports* aSubject,
                        const char16_t* aData)
 {
     if (!strcmp(aTopic, "xpcom-shutdown") && mSubprocess) {
-        if (mShutdownPending) {
-            // Wait for shutdown to complete, so that we receive any shutdown
-            // data (e.g. telemetry) from the child before we quit.
-            while (!mShutdownComplete) {
-                NS_ProcessNextEvent(nullptr, true);
-            }
-        } else {
-            // Just close the channel if we never tried shutting down.
-            ShutDownProcess(CLOSE_CHANNEL);
+        if (!mShutdownPending && mIPCOpen) {
+            ShutDownProcess(SEND_SHUTDOWN_MESSAGE);
+        }
+
+        // Wait for shutdown to complete, so that we receive any shutdown
+        // data (e.g. telemetry) from the child before we quit.
+        // This loop terminate prematurely based on mForceKillTimer.
+        while (mIPCOpen) {
+            NS_ProcessNextEvent(nullptr, true);
         }
         NS_ASSERTION(!mSubprocess, "Close should have nulled mSubprocess");
     }

dom/ipc/ContentParent.h

@@ -813,7 +813,7 @@ private:
     bool mCalledKillHard;
     bool mCreatedPairedMinidumps;
     bool mShutdownPending;
-    bool mShutdownComplete;
+    bool mIPCOpen;
 
     friend class CrashReporterParent;