Improve input handling for WaveAudioHandler.

media/audio/sounds/audio_stream_handler.h

 // Copyright 2013 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.
 
 #ifndef MEDIA_AUDIO_SOUNDS_AUDIO_STREAM_HANDLER_H_
 #define MEDIA_AUDIO_SOUNDS_AUDIO_STREAM_HANDLER_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/strings/string_piece.h"
@@ skipping 35 matching lines @@
   // and won't be changed during playback. Returns true iff new playback
   // was successfully started.
   //
   // NOTE: if current playback isn't at end of stream, playback request
   // is dropped, but true is returned.
   bool Play();
 
   // Stops current playback.
   void Stop();
 
-  const WavAudioHandler& wav_audio_handler() const { return wav_audio_; }
+  // If AudioStreamHandler is not initialized, this will return nullptr.
+  const WavAudioHandler* wav_audio_handler() const { return wav_audio_.get(); }
 
  private:
   friend class AudioStreamHandlerTest;
   friend class SoundsManagerTest;
 
   class AudioStreamContainer;
 
   static void SetObserverForTesting(TestObserver* observer);
   static void SetAudioSourceForTesting(
       AudioOutputStream::AudioSourceCallback* source);
 
-  WavAudioHandler wav_audio_;
+  scoped_ptr<WavAudioHandler> wav_audio_;
   scoped_ptr<AudioStreamContainer> stream_;
 
   bool initialized_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioStreamHandler);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_SOUNDS_AUDIO_STREAM_HANDLER_H_