Bug 1642849 shut down MediaTrackGraph from AudioContext when window will be destroyed r=padenot

Differential Revision: https://phabricator.services.mozilla.com/D74814

dom/base/nsGlobalWindowInner.cpp

@@ -1137,7 +1137,7 @@ void nsGlobalWindowInner::FreeInnerObjects() {
   NotifyWindowIDDestroyed("inner-window-destroyed");
 
   for (uint32_t i = 0; i < mAudioContexts.Length(); ++i) {
-    mAudioContexts[i]->Shutdown();
+    mAudioContexts[i]->OnWindowDestroy();
   }
   mAudioContexts.Clear();
 

dom/media/webaudio/AudioContext.cpp

@@ -743,11 +743,11 @@ nsISerialEventTarget* AudioContext::GetMainThread() const {
 
 void AudioContext::DisconnectFromOwner() {
   mIsDisconnecting = true;
-  Shutdown();
+  OnWindowDestroy();
   DOMEventTargetHelper::DisconnectFromOwner();
 }
 
-void AudioContext::Shutdown() {
+void AudioContext::OnWindowDestroy() {
   // Avoid resend the Telemetry data.
   if (!mIsShutDown) {
     MaybeUpdateAutoplayTelemetryWhenShutdown();
@@ -776,11 +776,20 @@ void AudioContext::Shutdown() {
   // PBrowser::Destroy() message before xpcom shutdown begins.
   ShutdownWorklet();
 
-  // For offline contexts, we can destroy the MediaTrackGraph at this point.
-  if (mIsOffline && mDestination) {
+  if (mDestination) {
+    // We can destroy the MediaTrackGraph at this point.
+    // Although there may be other clients using the graph, this graph is used
+    // only for clients in the same window and this window is going away.
+    // This will also interrupt any worklet script still running on the graph
+    // thread.
+    Graph()->ForceShutDown();
+    // AudioDestinationNodes on rendering offline contexts have a
+    // self-reference which needs removal.
+    if (mIsOffline) {
       mDestination->OfflineShutdown();
     }
   }
+}
 
 /* This runnable allows to fire the "statechange" event */
 class OnStateChangeTask final : public Runnable {

dom/media/webaudio/AudioContext.h

@@ -151,7 +151,7 @@ class AudioContext final : public DOMEventTargetHelper,
 
   virtual void DisconnectFromOwner() override;
 
-  void Shutdown();  // idempotent
+  void OnWindowDestroy();  // idempotent
 
   JSObject* WrapObject(JSContext* aCx,
                        JS::Handle<JSObject*> aGivenProto) override;

dom/media/webaudio/AudioDestinationNode.cpp

@@ -488,11 +488,8 @@ void AudioDestinationNode::OfflineShutdown() {
   MOZ_ASSERT(Context() && Context()->IsOffline(),
              "Should only be called on a valid OfflineAudioContext");
 
-  if (mTrack) {
-    mTrack->Graph()->MediaTrackGraph::ForceShutDown();
   mOfflineRenderingRef.Drop(this);
 }
-}
 
 JSObject* AudioDestinationNode::WrapObject(JSContext* aCx,
                                            JS::Handle<JSObject*> aGivenProto) {