Bug 1343787. Part 1 - allow MediaShutdownManager::Register() to fail. r=gerald

MozReview-Commit-ID: 2pnPnq4NlXN

--HG--
extra : rebase_source : c24c38ff5bad0902cc454e606a62e4d2bf60a602
extra : source : 2fe2c0b335ba6d1c17220c0bcabe645d771f77ac

dom/media/MediaShutdownManager.cpp

@@ -91,24 +91,29 @@ MediaShutdownManager::RemoveBlocker()
   DECODER_LOG(LogLevel::Debug, ("MediaShutdownManager::BlockShutdown() end."));
 }
 
-void
+nsresult
 MediaShutdownManager::Register(MediaDecoder* aDecoder)
 {
   MOZ_ASSERT(NS_IsMainThread());
-  MOZ_RELEASE_ASSERT(!mIsDoingXPCOMShutDown);
+  if (mIsDoingXPCOMShutDown) {
+    return NS_ERROR_ABORT;
+  }
   // Don't call Register() after you've Unregistered() all the decoders,
   // that's not going to work.
   MOZ_ASSERT(!mDecoders.Contains(aDecoder));
   mDecoders.PutEntry(aDecoder);
   MOZ_ASSERT(mDecoders.Contains(aDecoder));
   MOZ_ASSERT(mDecoders.Count() > 0);
+  return NS_OK;
 }
 
 void
 MediaShutdownManager::Unregister(MediaDecoder* aDecoder)
 {
   MOZ_ASSERT(NS_IsMainThread());
-  MOZ_ASSERT(mDecoders.Contains(aDecoder));
+  if (!mDecoders.Contains(aDecoder)) {
+    return;
+  }
   mDecoders.RemoveEntry(aDecoder);
   if (mIsDoingXPCOMShutDown && mDecoders.Count() == 0) {
     RemoveBlocker();

dom/media/MediaShutdownManager.h

@@ -62,7 +62,7 @@ public:
 
   // Notifies the MediaShutdownManager that it needs to track the shutdown
   // of this MediaDecoder.
-  void Register(MediaDecoder* aDecoder);
+  nsresult Register(MediaDecoder* aDecoder);
 
   // Notifies the MediaShutdownManager that a MediaDecoder that it was
   // tracking has shutdown, and it no longer needs to be shutdown in the