Make media::AudioRenderer inherit from media::TimeSource.

media/filters/audio_renderer_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Audio rendering unit utilizing an AudioRendererSink to output data.
 //
 // This class lives inside three threads during it's lifetime, namely:
 // 1. Render thread
 //    Where the object is created.
 // 2. Media thread (provided via constructor)
@@ skipping 16 matching lines @@
 #include "base/synchronization/lock.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/audio_renderer.h"
 #include "media/base/audio_renderer_sink.h"
 #include "media/base/decryptor.h"
 #include "media/filters/audio_renderer_algorithm.h"
 #include "media/filters/decoder_stream.h"
 
 namespace base {
 class SingleThreadTaskRunner;
+class TickClock;
 }
 
 namespace media {
 
 class AudioBufferConverter;
 class AudioBus;
 class AudioClock;
 class AudioHardwareConfig;
 class AudioSplicer;
 class DecryptingDemuxerStream;
@@ skipping 11 matching lines @@
   // |set_decryptor_ready_cb| is fired when the audio decryptor is available
   // (only applicable if the stream is encrypted and we have a decryptor).
   AudioRendererImpl(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
       AudioRendererSink* sink,
       ScopedVector<AudioDecoder> decoders,
       const SetDecryptorReadyCB& set_decryptor_ready_cb,
       AudioHardwareConfig* hardware_params);
   virtual ~AudioRendererImpl();
 
+  // TimeSource implementation.

[xhwang, 2014/07/21 22:10:06]

Since AudioRenderer inherits TimeSource, this is not necessarily true. Strictly
speaking this is included in AudioRenderer impl on l.77

+  virtual void StartTicking() OVERRIDE;
+  virtual void StopTicking() OVERRIDE;
+  virtual void SetPlaybackRate(float rate) OVERRIDE;
+  virtual void SetMediaTime(base::TimeDelta timestamp) OVERRIDE;
+  virtual base::TimeDelta CurrentMediaTime() OVERRIDE;
+
   // AudioRenderer implementation.
   virtual void Initialize(DemuxerStream* stream,
                           const PipelineStatusCB& init_cb,
                           const StatisticsCB& statistics_cb,
                           const TimeCB& time_cb,
                           const BufferingStateCB& buffering_state_cb,
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb) OVERRIDE;
-  virtual void StartRendering() OVERRIDE;
-  virtual void StopRendering() OVERRIDE;
-  virtual void SetMediaTime(base::TimeDelta time) OVERRIDE;
   virtual void Flush(const base::Closure& callback) OVERRIDE;
   virtual void Stop(const base::Closure& callback) OVERRIDE;
-  virtual void SetPlaybackRate(float rate) OVERRIDE;
   virtual void StartPlaying() OVERRIDE;
   virtual void SetVolume(float volume) OVERRIDE;
 
+  void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
+
  private:
   friend class AudioRendererImplTest;
 
   // Important detail: being in kPlaying doesn't imply that audio is being
   // rendered. Rather, it means that the renderer is ready to go. The actual
   // rendering of audio is controlled via Start/StopRendering().
   //
   //   kUninitialized
   //         | Initialize()
   //         |
@@ skipping 115 matching lines @@
   // Callbacks provided during Initialize().
   PipelineStatusCB init_cb_;
   TimeCB time_cb_;
   BufferingStateCB buffering_state_cb_;
   base::Closure ended_cb_;
   PipelineStatusCB error_cb_;
 
   // Callback provided to Flush().
   base::Closure flush_cb_;
 
+  scoped_ptr<base::TickClock> tick_clock_;
+
   // After Initialize() has completed, all variables below must be accessed
   // under |lock_|. ------------------------------------------------------------
   base::Lock lock_;
 
   // Algorithm for scaling audio.
   scoped_ptr<AudioRendererAlgorithm> algorithm_;
 
   // Simple state tracking variable.
   State state_;
 
   BufferingState buffering_state_;
 
   // Keep track of whether or not the sink is playing and whether we should be
   // rendering.
   bool rendering_;
   bool sink_playing_;
 
   // Keep track of our outstanding read to |decoder_|.
   bool pending_read_;
 
   // Keeps track of whether we received and rendered the end of stream buffer.
   bool received_end_of_stream_;
   bool rendered_end_of_stream_;
 
   scoped_ptr<AudioClock> audio_clock_;
+  base::TimeTicks last_render_ticks_;
 
   base::TimeDelta start_timestamp_;
 
   // End variables which must be accessed under |lock_|. ----------------------
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<AudioRendererImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_AUDIO_RENDERER_IMPL_H_