Implement suspend() and resume() for OfflineAudioContext

Source/modules/webaudio/AudioDestinationNode.h

Index: Source/modules/webaudio/AudioDestinationNode.h
diff --git a/Source/modules/webaudio/AudioDestinationNode.h b/Source/modules/webaudio/AudioDestinationNode.h
index 142ee084e4dcf33e042f448fb9d55c34eb478e3a..6bc689f55bbae9190bb3d4b56e883e4a08e0dc2d 100644
--- a/Source/modules/webaudio/AudioDestinationNode.h
+++ b/Source/modules/webaudio/AudioDestinationNode.h
@@ -56,6 +56,8 @@ public:
     virtual void startRendering() = 0;
     virtual void stopRendering() = 0;
 
+    virtual size_t quantizeTime(double) const { return 0; }

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

I think this is too vague.  Choose a more descriptive name.  Maybe
quantizeTimeToRenderingQuantum?  Add some comment on what this really does.

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

Yes, I agree. Will fix it.

+
 protected:
     // LocalAudioInputProvider allows us to expose an AudioSourceProvider for local/live audio input.
     // If there is local/live audio input, we call set() with the audio input data every render quantum.