Implement suspend() and resume() for OfflineAudioContext

Source/modules/webaudio/AudioContext.h

Index: Source/modules/webaudio/AudioContext.h
diff --git a/Source/modules/webaudio/AudioContext.h b/Source/modules/webaudio/AudioContext.h
index bfb33051c35606bc57ea36da3a23eabdf796e336..8db6416ef12191170ba89ce413831058f3074470 100644
--- a/Source/modules/webaudio/AudioContext.h
+++ b/Source/modules/webaudio/AudioContext.h
@@ -219,12 +219,12 @@ public:
     virtual const AtomicString& interfaceName() const override final;
     virtual ExecutionContext* executionContext() const override final;
 
-    DEFINE_ATTRIBUTE_EVENT_LISTENER(complete);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(statechange);
 
     void startRendering();
-    void fireCompletionEvent();
+    virtual void fireCompletionEvent();
     void notifyStateChange();
+    virtual bool shouldSuspendNow();

[Raymond Toy, 2015/05/28 16:37:35]

Isn't this only used by an offline context?

[hongchan, 2015/06/09 20:49:59]

This is used by OfflineAudioDestinatioNode. That's why I made it public.

[Raymond Toy, 2015/06/09 22:34:59]

Then why not make it a private method in OfflineAudioDestinationNode?

 
     // A context is considered closed if:
     //  - closeContext() has been called, even if the audio HW has not yet been
@@ -242,7 +242,13 @@ protected:
     explicit AudioContext(Document*);
     AudioContext(Document*, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
 
-    RefPtrWillBeMember<ScriptPromiseResolver> m_offlineResolver;
+    // Shared with OfflineAudioContext.
+    void setContextState(AudioContextState);
+    bool m_didInitializeContextGraphMutex;
+    bool m_isOfflineContext;
+    Member<AudioBuffer> m_renderTarget;
+    Member<AudioDestinationNode> m_destinationNode;

[Raymond Toy, 2015/05/28 16:37:35]

I think an offline context should use destination() to get this, so this member
variable doesn't need to be protected.  Maybe we should also add
isOfflineContext() method and renderTarget() method?

[hongchan, 2015/06/09 20:49:59]

Seems like a good idea. Will look into it.

+
 private:
     void initialize();
     void uninitialize();
@@ -262,7 +268,6 @@ private:
     // haven't finished playing.  Make sure to release them here.
     void releaseActiveSourceNodes();
 
-    Member<AudioDestinationNode> m_destinationNode;
     Member<AudioListener> m_listener;
 
     // Only accessed in the audio thread.
@@ -297,17 +302,9 @@ private:
 
     unsigned m_connectionCount;
 
-    // Graph locking.

[Raymond Toy, 2015/05/28 16:37:35]

Preserve these comments with the variable that you moved.  Also line 308.

[hongchan, 2015/06/09 20:49:59]

Will do!

-    bool m_didInitializeContextGraphMutex;
     RefPtr<DeferredTaskHandler> m_deferredTaskHandler;
 
-    Member<AudioBuffer> m_renderTarget;
-
-    bool m_isOfflineContext;
-
-    // The state of the AudioContext.
     AudioContextState m_contextState;
-    void setContextState(AudioContextState);
 
     AsyncAudioDecoder m_audioDecoder;