bug 1172377 change RunInStableState API to receive ownership of nsIRunnable r=roc

dom/base/nsContentUtils.cpp

@@ -5162,9 +5162,7 @@ nsContentUtils::RunInStableState(already_AddRefed<nsIRunnable> aRunnable,
     MOZ_ASSERT(aHandling == DispatchFailureHandling::IgnoreFailure);
     return;
   }
-  DebugOnly<nsresult> rv = appShell->RunInStableState(runnable);
-  MOZ_ASSERT(NS_SUCCEEDED(rv) ||
-             aHandling == DispatchFailureHandling::IgnoreFailure);
+  appShell->RunInStableState(runnable.forget());
 }
 
 void

widget/ScreenProxy.cpp

@@ -171,9 +171,9 @@ ScreenProxy::InvalidateCacheOnNextTick()
 
   nsCOMPtr<nsIAppShell> appShell = do_GetService(kAppShellCID);
   if (appShell) {
-    appShell->RunInStableState(
-      NS_NewRunnableMethod(this, &ScreenProxy::InvalidateCache)
-    );
+    nsCOMPtr<nsIRunnable> r =
+      NS_NewRunnableMethod(this, &ScreenProxy::InvalidateCache);
+    appShell->RunInStableState(r.forget());
   } else {
     // It's pretty bad news if we can't get the appshell. In that case,
     // let's just invalidate the cache right away.

widget/nsBaseAppShell.cpp

@@ -387,7 +387,8 @@ nsBaseAppShell::RunSyncSectionsInternal(bool aStable,
 }
 
 void
-nsBaseAppShell::ScheduleSyncSection(nsIRunnable* aRunnable, bool aStable)
+nsBaseAppShell::ScheduleSyncSection(already_AddRefed<nsIRunnable> aRunnable,
+                                    bool aStable)
 {
   NS_ASSERTION(NS_IsMainThread(), "Should be on main thread.");
 
@@ -444,16 +445,16 @@ nsBaseAppShell::Observe(nsISupports *subject, const char *topic,
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsBaseAppShell::RunInStableState(nsIRunnable* aRunnable)
+void
+nsBaseAppShell::RunInStableState(already_AddRefed<nsIRunnable> aRunnable)
 {
-  ScheduleSyncSection(aRunnable, true);
-  return NS_OK;
+  ScheduleSyncSection(mozilla::Move(aRunnable), true);
 }
 
 NS_IMETHODIMP
 nsBaseAppShell::RunBeforeNextEvent(nsIRunnable* aRunnable)
 {
-  ScheduleSyncSection(aRunnable, false);
+  nsCOMPtr<nsIRunnable> runnable = aRunnable;
+  ScheduleSyncSection(runnable.forget(), false);
   return NS_OK;
 }

widget/nsBaseAppShell.h

@@ -25,6 +25,8 @@ class nsBaseAppShell : public nsIAppShell, public nsIThreadObserver,
 public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSIAPPSHELL
+  void RunInStableState(already_AddRefed<nsIRunnable> runnable) override;
+
   NS_DECL_NSITHREADOBSERVER
   NS_DECL_NSIOBSERVER
 
@@ -94,7 +96,7 @@ private:
     }
   }
 
-  void ScheduleSyncSection(nsIRunnable* runnable, bool stable);
+  void ScheduleSyncSection(already_AddRefed<nsIRunnable> runnable, bool stable);
 
   struct SyncSection {
     SyncSection()

widget/nsIAppShell.idl

@@ -7,12 +7,15 @@
 #include "nsISupports.idl"
 
 interface nsIRunnable;
+%{ C++
+template <class T> struct already_AddRefed;
+%}
 
 /**
  * Interface for the native event system layer.  This interface is designed
  * to be used on the main application thread only.
  */
-[uuid(2d10ca53-f143-439a-bb2e-c1fbc71f6a05)]
+[uuid(3d09973e-3975-4fd4-b103-276300cc8437)]
 interface nsIAppShell : nsISupports
 {
   /**
@@ -71,16 +74,20 @@ interface nsIAppShell : nsISupports
    */
   readonly attribute unsigned long eventloopNestingLevel;
   
+%{ C++
   /**
-   * Allows running of a "synchronous section", in the form of an nsIRunnable
-   * once the event loop has reached a "stable state". We've reached a stable
-   * state when the currently executing task/event has finished, see:
+   * Add a "synchronous section", in the form of an nsIRunnable run once the
+   * event loop has reached a "stable state". |runnable| must not cause any
+   * queued events to be processed (i.e. must not spin the event loop). We've
+   * reached a stable state when the currently executing task/event has
+   * finished, see:
    * http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#synchronous-section
    * In practice this runs aRunnable once the currently executing event
    * finishes. If called multiple times per task/event, all the runnables will
    * be executed, in the order in which runInStableState() was called.
    */
-  void runInStableState(in nsIRunnable runnable);
+  virtual void RunInStableState(already_AddRefed<nsIRunnable> runnable) = 0;
+%}
 
   /**
    * Run the given runnable before the next iteration of the event loop (this

widget/nsScreenManagerProxy.cpp

@@ -200,9 +200,9 @@ nsScreenManagerProxy::InvalidateCacheOnNextTick()
 
   nsCOMPtr<nsIAppShell> appShell = do_GetService(kAppShellCID);
   if (appShell) {
-    appShell->RunInStableState(
-      NS_NewRunnableMethod(this, &nsScreenManagerProxy::InvalidateCache)
-    );
+    nsCOMPtr<nsIRunnable> r =
+      NS_NewRunnableMethod(this, &nsScreenManagerProxy::InvalidateCache);
+    appShell->RunInStableState(r.forget());
   } else {
     // It's pretty bad news if we can't get the appshell. In that case,
     // let's just invalidate the cache right away.