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(); }

[tommi (sloooow) - chröme, 2015/11/19 09:44:06]

can you add a DCHECK here for the current thread? (see cc file for usage of
base::NonThreadSafe)

[slan, 2015/11/19 18:57:16]

Does this class needs these? All data members are set in the ctor, and all work
is posted to the AudioManagerThread, which guarantees ordering. 

But to be consistent, I've added such a DCHECK to duration(), the replacement
for this method. There are should not be threading concerns, but this will help
find any nonsense and is consistent with the rest of the methods.

 
  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_