Introduce AudioClock to improve playback delay calculations.

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 19 matching lines @@
 #include "media/base/decryptor.h"
 #include "media/filters/audio_renderer_algorithm.h"
 #include "media/filters/decoder_stream.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 
+class AudioBufferConverter;
 class AudioBus;
-class AudioBufferConverter;
+class AudioHardwareConfig;
 class AudioSplicer;
+class BufferedAudioTracker;
 class DecryptingDemuxerStream;
-class AudioHardwareConfig;
 
 class MEDIA_EXPORT AudioRendererImpl
     : public AudioRenderer,
       NON_EXPORTED_BASE(public AudioRendererSink::RenderCallback) {
  public:
   // |task_runner| is the thread on which AudioRendererImpl will execute.
   //
   // |sink| is used as the destination for the rendered audio.
   //
   // |decoders| contains the AudioDecoders to use when initializing.
@@ skipping 214 matching lines @@
   // than nothing.
   base::TimeTicks earliest_end_time_;
   size_t total_frames_filled_;
 
   bool underflow_disabled_;
 
   // True if the renderer receives a buffer with kAborted status during preroll,
   // false otherwise. This flag is cleared on the next Preroll() call.
   bool preroll_aborted_;
 
+  scoped_ptr<BufferedAudioTracker> buffered_audio_tracker_;
+
   // 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_