bug 1217625 perform checks for transition to inactive outside of stream processing r=padenot

This will allow streams to be suspended when they are discovered inactive.
Suspending is not possible while iterating over stream lists for processing.

The approach of delaying the transition to inactive state may result in a
couple of extra processing iterations, but can save on the number of messages
that need to be created when compared to the approach of traversing downstream
nodes during stream processing.

--HG--
extra : rebase_source : b6707da5afa9323058b3f70b7743c13380618dad

dom/media/webaudio/AnalyserNode.cpp

@@ -72,7 +72,7 @@ public:
       if (mChunksToProcess <= 0) {
         if (mChunksToProcess != INT32_MIN) {
           mChunksToProcess = INT32_MIN;
-          aStream->CheckForInactive();
+          aStream->ScheduleCheckForInactive();
         }
         return;
       }

dom/media/webaudio/AudioNodeStream.cpp

@@ -576,7 +576,9 @@ AudioNodeStream::ProcessInput(GraphTime aFrom, GraphTime aTo, uint32_t aFlags)
     }
     if (finished) {
       mMarkAsFinishedAfterThisBlock = true;
-      CheckForInactive();
+      if (mIsActive) {
+        ScheduleCheckForInactive();
+      }
     }
 
     if (mDisabledTrackIDs.Contains(static_cast<TrackID>(AUDIO_TRACK))) {
@@ -707,6 +709,29 @@ AudioNodeStream::SetActive()
   }
 }
 
+class AudioNodeStream::CheckForInactiveMessage final : public ControlMessage
+{
+public:
+  explicit CheckForInactiveMessage(AudioNodeStream* aStream) :
+    ControlMessage(aStream) {}
+  virtual void Run() override
+  {
+    auto ns = static_cast<AudioNodeStream*>(mStream);
+    ns->CheckForInactive();
+  }
+};
+
+void
+AudioNodeStream::ScheduleCheckForInactive()
+{
+  if (mActiveInputCount > 0 && !mMarkAsFinishedAfterThisBlock) {
+    return;
+  }
+
+  nsAutoPtr<CheckForInactiveMessage> message(new CheckForInactiveMessage(this));
+  GraphImpl()->RunMessageAfterProcessing(Move(message));
+}
+
 void
 AudioNodeStream::CheckForInactive()
 {

dom/media/webaudio/AudioNodeStream.h

@@ -164,6 +164,19 @@ public:
    * active.
    */
   void SetActive();
+  /*
+   * ScheduleCheckForInactive() is called during stream processing when the
+   * engine transitions from active to inactive, or the stream finishes.  It
+   * schedules a call to CheckForInactive() after stream processing.
+   */
+  void ScheduleCheckForInactive();
+
+protected:
+  class AdvanceAndResumeMessage;
+  class CheckForInactiveMessage;
+
+  virtual void DestroyImpl() override;
+
   /*
    * CheckForInactive() is called when the engine transitions from active to
    * inactive, or an active input is removed, or the stream finishes.  If the
@@ -173,11 +186,6 @@ public:
    */
   void CheckForInactive();
 
-protected:
-  class AdvanceAndResumeMessage;
-
-  virtual void DestroyImpl() override;
-
   void AdvanceOutputSegment();
   void FinishOutput();
   void AccumulateInputChunk(uint32_t aInputIndex, const AudioBlock& aChunk,

dom/media/webaudio/BiquadFilterNode.cpp

@@ -149,7 +149,7 @@ public:
       if (!hasTail) {
         if (!mBiquads.IsEmpty()) {
           mBiquads.Clear();
-          aStream->CheckForInactive();
+          aStream->ScheduleCheckForInactive();
 
           RefPtr<PlayingRefChangeHandler> refchanged =
             new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::RELEASE);

dom/media/webaudio/ConvolverNode.cpp

@@ -121,7 +121,7 @@ public:
       } else {
         if (mLeftOverData != INT32_MIN) {
           mLeftOverData = INT32_MIN;
-          aStream->CheckForInactive();
+          aStream->ScheduleCheckForInactive();
           RefPtr<PlayingRefChanged> refchanged =
             new PlayingRefChanged(aStream, PlayingRefChanged::RELEASE);
           aStream->Graph()->

dom/media/webaudio/DelayNode.cpp

@@ -91,7 +91,7 @@ public:
     } else {
       if (mLeftOverData != INT32_MIN) {
         mLeftOverData = INT32_MIN;
-        aStream->CheckForInactive();
+        aStream->ScheduleCheckForInactive();
 
         // Delete our buffered data now we no longer need it
         mBuffer.Reset();

dom/media/webaudio/PannerNode.cpp

@@ -150,7 +150,7 @@ public:
       } else {
         if (mLeftOverData != INT_MIN) {
           mLeftOverData = INT_MIN;
-          aStream->CheckForInactive();
+          aStream->ScheduleCheckForInactive();
           mHRTFPanner->reset();
 
           RefPtr<PlayingRefChangeHandler> refchanged =