Change default audio device from "plug:default" to "default".

media/audio/linux/alsa_output.h

 // Copyright (c) 2009 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.
 //
 // Creates an output stream based on the ALSA PCM interface.  The current
 // implementation creates one thread per ALSA playback handle that is
 // responsible for synchronously pulling data from the audio data source.
 //
 // This output stream buffers in two places:
 //   (1) In the ALSA device
@@ skipping 25 matching lines @@
 #include "base/scoped_ptr.h"
 #include "base/thread.h"
 #include "media/audio/audio_output.h"
 
 class Thread;
 
 class AlsaPCMOutputStream :
     public AudioOutputStream,
     public base::RefCountedThreadSafe<AlsaPCMOutputStream> {
  public:
-  // Set to "plug:default" which should allow ALSA to do whatever is
-  // necessary to simulate an audio device capable of handling our PCMs.
+  // Set to "default" which should avoid locking the sound device and allow
+  // ALSA to multiplex sound from different processes that want to write PCM
+  // data.
   static const char* kDefaultDevice;
 
   // Create a PCM Output stream for the ALSA device identified by
   // |device_name|.  If unsure of hte device_name, use kDefaultDevice.
   AlsaPCMOutputStream(const std::string& device_name,
                       int min_buffer_ms,
                       AudioManager::Format format,
                       int channels,
                       int sample_rate,
                       char bits_per_sample);
@@ skipping 98 matching lines @@
   // FillAlsaDeviceBuffer() methods.
   bool device_write_suspended_;
 
   // Flag indicating that the resources are already cleaned.
   bool resources_released_;
 
   DISALLOW_COPY_AND_ASSIGN(AlsaPCMOutputStream);
 };
 
 #endif  // MEDIA_AUDIO_LINUX_ALSA_OUTPUT_H_