Implementation of 'AudioContext.getOutputTimestamp' method

third_party/WebKit/Source/platform/audio/AudioDestination.h

Index: third_party/WebKit/Source/platform/audio/AudioDestination.h
diff --git a/third_party/WebKit/Source/platform/audio/AudioDestination.h b/third_party/WebKit/Source/platform/audio/AudioDestination.h
index dda3527f57476e3697025958418f64c07573959d..60a862e7d2febce47428dfa79242d1b22c08adb1 100644
--- a/third_party/WebKit/Source/platform/audio/AudioDestination.h
+++ b/third_party/WebKit/Source/platform/audio/AudioDestination.h
@@ -82,7 +82,11 @@ class PLATFORM_EXPORT AudioDestination : public WebAudioDevice::RenderCallback,
   // WebAudioDevice::RenderCallback
   void render(const WebVector<float*>& sourceData,
               const WebVector<float*>& audioData,
-              size_t numberOfFrames) override;
+              size_t numberOfFrames,
+              double delay,           // Output delay in seconds.

[miu, 2016/11/29 20:51:04]

suggestion: Just in case others get confused the way I did: Could you write a
method comment like: "|delay| and |delayTimestamp| are high-precision
measurements of the state of the system in the recent past. To be clear, |delay|
does *not* represent the point-in-time at which the first rendered sample will
be played out."

[miu, 2016/12/01 05:33:17]

Didn't see this addressed in PS10 (and looks like the extra code comments should
go in 	third_party/WebKit/public/platform/WebAudioDevice.h).

[Mikhail, 2016/12/02 11:48:21]

Done. Thanks for suggestion!

+              double delayTimestamp,  // System timestamp in seconds when
+                                      // |delay| was obtained.
+              size_t priorFramesSkipped) override;
 
   // AudioSourceProvider
   void provideInput(AudioBus*, size_t framesToProcess) override;
@@ -109,6 +113,10 @@ class PLATFORM_EXPORT AudioDestination : public WebAudioDevice::RenderCallback,
 
   std::unique_ptr<AudioFIFO> m_inputFifo;
   std::unique_ptr<AudioPullFIFO> m_fifo;
+
+  size_t m_framesElapsed;
+  AudioIOPosition m_outputPosition;
+  base::TimeTicks m_outputPositionReceivedTimestamp;
 };
 
 }  // namespace blink