Implement suspend() and resume() for OfflineAudioContext

Source/modules/webaudio/OfflineAudioContext.h

 /*
  * Copyright (C) 2012, 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 18 matching lines @@
 #include "modules/webaudio/AudioContext.h"
 
 namespace blink {
 
 class ExceptionState;
 
 class MODULES_EXPORT OfflineAudioContext final : public AudioContext {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static OfflineAudioContext* create(ExecutionContext*, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState&);
-
     virtual ~OfflineAudioContext();
 
+    virtual bool suspendIfNecessary();
+
+    // IDL implementations.
     ScriptPromise startOfflineRendering(ScriptState*);
+    ScriptPromise suspendOfflineRendering(ScriptState*, double suspendTime);
+    ScriptPromise resumeOfflineRendering(ScriptState*);
+
 private:
     OfflineAudioContext(Document*, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
+
+    WillBeHeapVector<RefPtrWillBeMember<ScriptPromiseResolver>> m_offlineSuspendResolvers;
+    WillBeHeapVector<RefPtrWillBeMember<ScriptPromiseResolver>> m_offlineResumeResolvers;

[Raymond Toy, 2015/05/13 17:16:08]

As discussed earlier, the online context is going to merge the suspend resume
resolvers onto one list/vector so that they happen in order.  Does that matter
here?

[hongchan, 2015/05/13 17:30:53]

Yes. That makes sense. These are actually not used in this patch at all - they
are just placeholders.

+
+    bool m_isSuspendScheduled;
+    double m_suspendTime;
 };
 
 } // namespace blink
 
 #endif // OfflineAudioContext_h