Safe and reliable fix for 2 race conditions.

content/renderer/media/audio_device.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.
 //
 // Low-latency audio rendering unit utilizing audio output stream provided
 // by browser process through IPC.
 //
 // Relationship of classes.
 //
 //  AudioOutputController                AudioDevice
@@ skipping 83 matching lines @@
 
   // Methods called on main render thread -------------------------------------
 
   // Minimal constructor where Initialize() must be called later.
   AudioDevice();
 
   AudioDevice(size_t buffer_size,
               int channels,
               double sample_rate,
               RenderCallback* callback);
-  virtual ~AudioDevice();
 
   void Initialize(size_t buffer_size,
                   int channels,
                   double sample_rate,
                   AudioParameters::Format latency_format,
                   RenderCallback* callback);
   bool IsInitialized();
 
   // Starts audio playback.
   void Start();
@@ skipping 56 matching lines @@
    private:
     // Magic required by ref_counted.h to avoid any code deleting the object
     // accidently while there are references to it.
     friend class base::RefCountedThreadSafe<AudioSocket>;
     ~AudioSocket() { }
 
     base::Lock lock_;
     base::SyncSocket socket_;
   };
 
+  // Magic required by ref_counted.h to avoid any code deleting the object
+  // accidently while there are references to it.
+  friend class base::RefCountedThreadSafe<AudioDevice>;
+  virtual ~AudioDevice();
+
   // Methods called on IO thread ----------------------------------------------
   // The following methods are tasks posted on the IO thread that needs to
   // be executed on that thread. They interact with AudioMessageFilter and
   // sends IPC messages on that thread.
   void InitializeOnIOThread(const AudioParameters& params);
   void PlayOnIOThread();
   void PauseOnIOThread(bool flush);
   void ShutDownOnIOThread(base::WaitableEvent* completion);
   void SetVolumeOnIOThread(double volume);
 
@@ skipping 61 matching lines @@
 
   // Protects lifetime of:
   // audio_socket_
   // audio_thread_
   base::Lock lock_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioDevice);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_H_