Reland: Add Stop() to AudioDecoder. (https://codereview.chromium.org/126793002/)

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 79 matching lines @@
   void set_now_cb_for_testing(const NowCB& now_cb) {
     now_cb_ = now_cb;
   }
 
  private:
   friend class AudioRendererImplTest;
 
   // TODO(acolwell): Add a state machine graph.
   enum State {
     kUninitialized,
+    kInitializing,
     kPaused,
     kFlushing,
     kPrerolling,
     kPlaying,
     kStopped,
     kUnderflow,
     kRebuffering,
   };
 
   // Callback from the audio decoder delivering decoded audio samples.
@@ skipping 162 matching lines @@
   bool preroll_aborted_;
 
   // End variables which must be accessed under |lock_|. ----------------------
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_AUDIO_RENDERER_IMPL_H_