Bug 1541467 - Handle situations where the document is not available from the AudioContext. r=karlt

Differential Revision: https://phabricator.services.mozilla.com/D25955

--HG--
extra : moz-landing-system : lando

dom/media/MediaStreamGraph.cpp

@@ -3288,9 +3288,16 @@ MediaStreamGraph* MediaStreamGraph::CreateNonRealtimeInstance(
     TrackRate aSampleRate, nsPIDOMWindowInner* aWindow) {
   MOZ_ASSERT(NS_IsMainThread(), "Main thread only");
 
+  AbstractThread* mainThread = AbstractThread::MainThread();
+  // aWindow can be null when the document is being unlinked, so this works when
+  // with a generic main thread if that's the case.
+  if (aWindow) {
+    mainThread =
+        aWindow->AsGlobal()->AbstractMainThreadFor(TaskCategory::Other);
+  }
+
   MediaStreamGraphImpl* graph = new MediaStreamGraphImpl(
-      OFFLINE_THREAD_DRIVER, DIRECT_DRIVER, aSampleRate,
-      aWindow->AsGlobal()->AbstractMainThreadFor(TaskCategory::Other));
+      OFFLINE_THREAD_DRIVER, DIRECT_DRIVER, aSampleRate, mainThread);
 
   LOG(LogLevel::Debug, ("Starting up Offline MediaStreamGraph %p", graph));
 

dom/media/webaudio/AudioDestinationNode.cpp

@@ -336,6 +336,8 @@ AudioDestinationNode::AudioDestinationNode(AudioContext* aContext,
     return;
   }
 
+  // GetParentObject can return nullptr here. This will end up creating another
+  // MediaStreamGraph
   MediaStreamGraph* graph = MediaStreamGraph::GetInstance(
       MediaStreamGraph::AUDIO_THREAD_DRIVER, aContext->GetParentObject(),
       aContext->SampleRate());
@@ -377,6 +379,8 @@ AudioNodeStream* AudioDestinationNode::Stream() {
 
   MOZ_ASSERT(mIsOffline, "Realtime streams are created in constructor");
 
+  // GetParentObject can return nullptr here when the document has been
+  // unlinked.
   MediaStreamGraph* graph = MediaStreamGraph::CreateNonRealtimeInstance(
       context->SampleRate(), context->GetParentObject());
   AudioNodeEngine* engine = new OfflineDestinationNodeEngine(this);

dom/media/webaudio/BiquadFilterNode.cpp

@@ -232,7 +232,10 @@ BiquadFilterNode::BiquadFilterNode(AudioContext* aContext)
           new AudioParam(this, BiquadFilterNodeEngine::DETUNE, "detune", 0.f)),
       mQ(new AudioParam(this, BiquadFilterNodeEngine::Q, "Q", 1.f)),
       mGain(new AudioParam(this, BiquadFilterNodeEngine::GAIN, "gain", 0.f)) {
-  uint64_t windowID = aContext->GetParentObject()->WindowID();
+  uint64_t windowID = 0;
+  if (aContext->GetParentObject()) {
+    windowID = aContext->GetParentObject()->WindowID();
+  }
   BiquadFilterNodeEngine* engine =
       new BiquadFilterNodeEngine(this, aContext->Destination(), windowID);
   mStream = AudioNodeStream::Create(

dom/media/webaudio/ConvolverNode.cpp

@@ -385,7 +385,14 @@ ConvolverNode::ConvolverNode(AudioContext* aContext)
     : AudioNode(aContext, 2, ChannelCountMode::Clamped_max,
                 ChannelInterpretation::Speakers),
       mNormalize(true) {
-  uint64_t windowID = aContext->GetParentObject()->WindowID();
+  uint64_t windowID;
+  if (aContext->GetParentObject()) {
+    windowID = aContext->GetParentObject()->WindowID();
+  } else {
+    // This is used to send a message to the developer console, but the page is
+    // being closed so it doesn't matter too much.
+    windowID = 0;
+  }
   ConvolverNodeEngine* engine =
       new ConvolverNodeEngine(this, mNormalize, windowID);
   mStream = AudioNodeStream::Create(

dom/media/webaudio/IIRFilterNode.cpp

@@ -148,7 +148,10 @@ IIRFilterNode::IIRFilterNode(AudioContext* aContext,
   // We check that this is exactly equal to one later in blink/IIRFilter.cpp
   elements[0] = 1.0;
 
-  uint64_t windowID = aContext->GetParentObject()->WindowID();
+  uint64_t windowID = 0;
+  if (aContext->GetParentObject()) {
+    windowID = aContext->GetParentObject()->WindowID();
+  }
   IIRFilterNodeEngine* engine = new IIRFilterNodeEngine(
       this, aContext->Destination(), mFeedforward, mFeedback, windowID);
   mStream = AudioNodeStream::Create(

dom/media/webaudio/MediaStreamAudioDestinationNode.cpp

@@ -71,10 +71,18 @@ MediaStreamAudioDestinationNode::MediaStreamAudioDestinationNode(
                 ChannelInterpretation::Speakers),
       mDOMStream(DOMAudioNodeMediaStream::CreateTrackUnionStreamAsInput(
           GetOwner(), this, aContext->Graph())) {
-  // Ensure an audio track with the correct ID is exposed to JS
-  Document* doc = aContext->GetParentObject()->GetExtantDoc();
+  // Ensure an audio track with the correct ID is exposed to JS. If we can't get
+  // a principal here because the document is not available, pass in a null
+  // principal. This happens in edge cases when the document is being unloaded
+  // and it does not matter too much to have something working as long as it's
+  // not dangerous.
+  nsCOMPtr<nsIPrincipal> principal = nullptr;
+  if (aContext->GetParentObject()) {
+    Document* doc = aContext->GetParentObject()->GetExtantDoc();
+    principal = doc->NodePrincipal();
+  }
   RefPtr<MediaStreamTrackSource> source =
-      new AudioDestinationTrackSource(this, doc->NodePrincipal());
+      new AudioDestinationTrackSource(this, principal);
   RefPtr<MediaStreamTrack> track = mDOMStream->CreateDOMTrack(
       AudioNodeStream::AUDIO_TRACK, MediaSegment::AUDIO, source,
       MediaTrackConstraints());