Bug 1191112 part 3 - Don't touch the widget anymore if it has been destroyed during the fullscreen transition. r=smaug

--HG--
extra : source : c07ef0526ac1098a949e91bbf3cf4f34de577e2e

dom/base/nsGlobalWindow.cpp

@@ -6358,6 +6358,12 @@ FullscreenTransitionTask::Run()
 {
   Stage stage = mStage;
   mStage = Stage(mStage + 1);
+  if (MOZ_UNLIKELY(mWidget->Destroyed())) {
+    // If the widget has been destroyed before we get here, don't try to
+    // do anything more. Just let it go and release ourselves.
+    NS_WARNING("The widget to fullscreen has been destroyed");
+    return NS_OK;
+  }
   if (stage == eBeforeToggle) {
     mWidget->PerformFullscreenTransition(nsIWidget::eBeforeFullscreenToggle,
                                          mDuration.mFadeIn, mTransitionData,