Implement suspend/resume for AudioContext

Source/modules/webaudio/AudioContext.h

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 #ifndef AudioContext_h
 #define AudioContext_h
 
+#include "bindings/core/v8/ScriptPromise.h"
+#include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventListener.h"
 #include "modules/EventTargetModules.h"
 #include "modules/webaudio/AsyncAudioDecoder.h"
 #include "modules/webaudio/AudioDestinationNode.h"
 #include "platform/audio/AudioBus.h"
 #include "platform/heap/Handle.h"
 #include "wtf/HashSet.h"
 #include "wtf/MainThread.h"
 #include "wtf/OwnPtr.h"
@@ skipping 83 matching lines @@
     ScriptProcessorNode* createScriptProcessor(size_t bufferSize, ExceptionState&);
     ScriptProcessorNode* createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, ExceptionState&);
     ScriptProcessorNode* createScriptProcessor(size_t bufferSize, size_t numberOfInputChannels, size_t numberOfOutputChannels, ExceptionState&);
     ChannelSplitterNode* createChannelSplitter(ExceptionState&);
     ChannelSplitterNode* createChannelSplitter(size_t numberOfOutputs, ExceptionState&);
     ChannelMergerNode* createChannelMerger(ExceptionState&);
     ChannelMergerNode* createChannelMerger(size_t numberOfInputs, ExceptionState&);
     OscillatorNode* createOscillator();
     PeriodicWave* createPeriodicWave(Float32Array* real, Float32Array* imag, ExceptionState&);
 
+    // Pause/Resume
+    void suspendContext();
+    ScriptPromise resumeContext(ScriptState*);
+
     // When a source node has no more processing to do (has finished playing), then it tells the context to dereference it.
     void notifyNodeFinishedProcessing(AudioNode*);
 
     // Called at the start of each render quantum.
     void handlePreRenderTasks();
 
     // Called at the end of each render quantum.
     void handlePostRenderTasks();
 
     // Called periodically at the end of each render quantum to dereference finished source nodes.
@@ skipping 18 matching lines @@
 
     // Keeps track of the number of connections made.
     void incrementConnectionCount()
     {
         ASSERT(isMainThread());
         m_connectionCount++;
     }
 
     unsigned connectionCount() const { return m_connectionCount; }
 
+    void resolvePromisesForResume();
+    void resolvePromisesForResumeOnMainThread();

[yhirano, 2014/10/08 01:12:14]

These function can be private.

+
     //
     // Thread Safety and Graph Locking:
     //
 
     void setAudioThread(ThreadIdentifier thread) { m_audioThread = thread; } // FIXME: check either not initialized or the same
     ThreadIdentifier audioThread() const { return m_audioThread; }
     bool isAudioThread() const;
 
     void lock();
     bool tryLock();
@@ skipping 88 matching lines @@
     GC_PLUGIN_IGNORE("http://crbug.com/404527")
     Vector<AudioNode*> m_finishedNodes;
 
     // List of source nodes. This is either accessed when the graph lock is
     // held, or on the main thread when the audio thread has finished.
     // Oilpan: This Vector holds connection references. We must call
     // AudioNode::makeConnection when we add an AudioNode to this, and must call
     // AudioNode::breakConnection() when we remove an AudioNode from this.
     HeapVector<Member<AudioNode> > m_referencedNodes;
 
+    GC_PLUGIN_IGNORE("http://crbug.com/404527")
+    Vector<RefPtr<ScriptPromiseResolver> > m_resumePromises;
+    // True if we're in the process of resolving promises for resume().  Resolving can take some
+    // 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;
+
     class AudioNodeDisposer {
     public:
         explicit AudioNodeDisposer(AudioNode& node) : m_node(node) { }
         ~AudioNodeDisposer();
 
     private:
         AudioNode& m_node;
     };
     HeapHashMap<WeakMember<AudioNode>, OwnPtr<AudioNodeDisposer> > m_liveNodes;
 
@@ skipping 59 matching lines @@
     HashSet<AudioNode*> m_deferredCountModeChange;
 
     // 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 // AudioContext_h