Don't fallback if we've successfully opened a stream previously.

media/audio/audio_output_dispatcher_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.
 
 // AudioOutputDispatcherImpl is an implementation of AudioOutputDispatcher.
 //
 // To avoid opening and closing audio devices more frequently than necessary,
 // each dispatcher has a pool of inactive physical streams. A stream is closed
 // only if it hasn't been used for a certain period of time (specified via the
 // constructor).
@@ skipping 22 matching lines @@
 
 class MEDIA_EXPORT AudioOutputDispatcherImpl : public AudioOutputDispatcher {
  public:
   // |close_delay_ms| specifies delay after the stream is paused until
   // the audio device is closed.
   AudioOutputDispatcherImpl(AudioManager* audio_manager,
                             const AudioParameters& params,
                             const base::TimeDelta& close_delay);
 
   // Opens a new physical stream if there are no pending streams in
-  // |idle_streams_|.
+  // |idle_streams_|.  Do not call Close() or Stop() if this method fails.
   virtual bool OpenStream() OVERRIDE;
 
   // If there are pending streams in |idle_streams_| then it reuses one of
   // them, otherwise creates a new one.
   virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback,
                            AudioOutputProxy* stream_proxy) OVERRIDE;
 
   // Holds the physical stream temporarily in |pausing_streams_| and then
   // |stream| is  added to the pool of pending streams (i.e. |idle_streams_|).
   virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE;
@@ skipping 39 matching lines @@
   base::DelayTimer<AudioOutputDispatcherImpl> close_timer_;
 
   AudioStreamMap proxy_to_physical_map_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcherImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_