Stop DecryptingDemuxerStream in AudioRendererImpl::Stop().

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 166 matching lines @@
   // completed.
   void DoFlush_Locked();
 
   // Calls |decoder_|.Reset() and arranges for ResetDecoderDone() to get
   // called when the reset completes.
   void ResetDecoder();
 
   // Called when the |decoder_|.Reset() has completed.
   void ResetDecoderDone();
 
+  void StopDecoder();

[ddorwin, 2014/02/14 19:49:30]

Add something like:
// Stops the decoder if present. Ensures stop_cb_ is called.

[xhwang, 2014/02/14 21:14:37]

Done.

+
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   base::WeakPtrFactory<AudioRendererImpl> weak_factory_;
   base::WeakPtr<AudioRendererImpl> weak_this_;
 
   scoped_ptr<AudioSplicer> splicer_;
 
   // The sink (destination) for rendered audio. |sink_| must only be accessed
   // on |task_runner_|. |sink_| must never be called under |lock_| or else we
   // may deadlock between |task_runner_| and the audio callback thread.
   scoped_refptr<media::AudioRendererSink> sink_;
@@ skipping 79 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_