Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h

Index: third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h b/third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h
index dc7fe45b785aa4c552a80638aed3a35d425c3ec1..ad9a8e2e69b9fabb7537c112bcb7b8ca689d22a4 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h
+++ b/third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h
@@ -39,7 +39,7 @@ class BaseAudioContext;
 
 class AudioDestinationHandler : public AudioHandler, public AudioIOCallback {
  public:
-  AudioDestinationHandler(AudioNode&, float sampleRate);
+  AudioDestinationHandler(AudioNode&);
   ~AudioDestinationHandler() override;
 
   // AudioHandler
@@ -65,6 +65,9 @@ class AudioDestinationHandler : public AudioHandler, public AudioIOCallback {
   virtual void startRendering() = 0;
   virtual void stopRendering() = 0;
 
+  virtual double sampleRate() const = 0;
+  virtual int framesPerBuffer() const = 0;

[Raymond Toy, 2016/11/30 21:50:27]

Please add comment on what framesPerBuffer actually returns.  I don't know what
a "buffer" is in this context.

[Andrew MacPherson, 2016/12/01 12:11:56]

Done.

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