Implement suspend() and resume() for OfflineAudioContext

Source/modules/webaudio/AbstractAudioContext.h

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 142 matching lines @@
     ChannelSplitterNode* createChannelSplitter(ExceptionState&);
     ChannelSplitterNode* createChannelSplitter(size_t numberOfOutputs, ExceptionState&);
     ChannelMergerNode* createChannelMerger(ExceptionState&);
     ChannelMergerNode* createChannelMerger(size_t numberOfInputs, ExceptionState&);
     OscillatorNode* createOscillator(ExceptionState&);
     PeriodicWave* createPeriodicWave(DOMFloat32Array* real, DOMFloat32Array* imag, ExceptionState&);
 
     // Close
     virtual ScriptPromise closeContext(ScriptState*) = 0;
 
-    // Suspend/Resume
+    // We have 2 suspend methods for online and offline audio context with
+    // different method signature.

[Raymond Toy, 2015/07/15 20:59:13]

Maybe comment that the first can only be used for online and the second only for
offline?

[hongchan, 2015/07/15 23:24:22]

Done.

     virtual ScriptPromise suspendContext(ScriptState*) = 0;
+    virtual ScriptPromise suspendContext(ScriptState*, double) = 0;
+
+    // Resume
     virtual ScriptPromise resumeContext(ScriptState*) = 0;
 
     // When a source node has started processing and needs to be protected,
     // this method tells the context to protect the node.
     //
     // The context itself keeps a reference to all source nodes.  The source
     // nodes, then reference all nodes they're connected to.  In turn, these
     // nodes reference all nodes they're connected to.  All nodes are ultimately
     // connected to the AudioDestinationNode.  When the context release a source
     // node, it will be deactivated from the rendering graph along with all
@@ skipping 38 matching lines @@
 #endif
     using AutoLocker = DeferredTaskHandler::AutoLocker;
 
     // Returns the maximum numuber of channels we can support.
     static unsigned maxNumberOfChannels() { return MaxNumberOfChannels;}
 
     // EventTarget
     const AtomicString& interfaceName() const final;
     ExecutionContext* executionContext() const final;
 
-    DEFINE_ATTRIBUTE_EVENT_LISTENER(complete);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(statechange);
 
     void startRendering();
-    void fireCompletionEvent();
     void notifyStateChange();
 
+    // TODO(hongchan): move this to OfflineAudioContext.
+    AudioBuffer* renderTarget() const { return m_renderTarget.get(); }
+
     // A context is considered closed if:
     //  - closeContext() has been called.
     //  - it has been stopped by its execution context.
     virtual bool isContextClosed() const { return m_isCleared; }
 
     // Get the security origin for this audio context.
     SecurityOrigin* securityOrigin() const;
 
 protected:
     explicit AbstractAudioContext(Document*);
     AbstractAudioContext(Document*, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
 
     void setContextState(AudioContextState);
     virtual void didClose() {}
     void uninitialize();
 
-    RefPtrWillBeMember<ScriptPromiseResolver> m_offlineResolver;
+    // RefPtrWillBeMember<ScriptPromiseResolver> m_offlineResolver;
 
     // FIXME(dominicc): Move m_resumeResolvers to AudioContext, because only
     // it creates these Promises.
     // Vector of promises created by resume(). It takes time to handle them, so we collect all of
     // the promises here until they can be resolved or rejected.
     WillBeHeapVector<RefPtrWillBeMember<ScriptPromiseResolver>> m_resumeResolvers;
 private:
     void initialize();
 
     bool m_isCleared;
@@ skipping 36 matching lines @@
     // time and the audio context process loop is very fast, so we don't want to call resolve an
     // excessive number of times.
     bool m_isResolvingResumePromises;
 
     unsigned m_connectionCount;
 
     // Graph locking.
     bool m_didInitializeContextGraphMutex;
     RefPtr<DeferredTaskHandler> m_deferredTaskHandler;
 
+    // For offline audio context.
+    // TODO(hongchan): move this to OfflineAudioContext class.
     Member<AudioBuffer> m_renderTarget;
 
     // The state of the AbstractAudioContext.
     AudioContextState m_contextState;
 
     AsyncAudioDecoder m_audioDecoder;
 
     // Tries to handle AudioBufferSourceNodes that were started but became disconnected or was never
     // connected. Because these never get pulled anymore, they will stay around forever. So if we
     // can, try to stop them so they can be collected.
     void handleStoppableSourceNodes();
 
     // This is considering 32 is large enough for multiple channels audio.
     // It is somewhat arbitrary and could be increased if necessary.
     enum { MaxNumberOfChannels = 32 };
 };
 
 } // namespace blink
 
 #endif // AbstractAudioContext_h