Use base::TickClock in media::AudioRendererImpl instead of a callback.

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 62 matching lines @@
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb) OVERRIDE;
   virtual void StartRendering() OVERRIDE;
   virtual void StopRendering() 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 StartPlayingFrom(base::TimeDelta timestamp) OVERRIDE;
   virtual void SetVolume(float volume) OVERRIDE;
 
-  // Allows injection of a custom time callback for non-realtime testing.
-  typedef base::Callback<base::TimeTicks()> NowCB;
-  void set_now_cb_for_testing(const NowCB& now_cb) {
-    now_cb_ = now_cb;
-  }
-
  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_;
 
-  // Typically calls base::TimeTicks::Now() but can be overridden by a test.
-  NowCB now_cb_;
-
   // 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_;
 
@@ skipping 19 matching lines @@
 
   // 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_