Revert 119769 - Switch AudioDevice classes from SyncSocket to CancelableSyncSocket.

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 124 matching lines @@
   virtual void OnRequestPacket(AudioBuffersState buffers_state) OVERRIDE;
   virtual void OnStateChanged(AudioStreamState state) OVERRIDE;
   virtual void OnCreated(base::SharedMemoryHandle handle,
                          uint32 length) OVERRIDE;
   virtual void OnLowLatencyCreated(base::SharedMemoryHandle handle,
                                    base::SyncSocket::Handle socket_handle,
                                    uint32 length) OVERRIDE;
   virtual void OnVolume(double volume) OVERRIDE;
 
  private:
+  // Encapsulate socket into separate class to avoid double-close.
+  // Class is ref-counted to avoid potential race condition if audio device
+  // is deleted simultaneously with audio thread stopping.
+  class AudioSocket : public base::RefCountedThreadSafe<AudioSocket> {
+   public:
+    explicit AudioSocket(base::SyncSocket::Handle socket_handle)
+        : socket_(socket_handle) {
+    }
+    base::SyncSocket* socket() {
+      return &socket_;
+    }
+    void Close() {
+      // Close() should be thread-safe, obtain the lock.
+      base::AutoLock auto_lock(lock_);
+      socket_.Close();
+    }
+
+   private:
+    // Magic required by ref_counted.h to avoid any code deleting the object
+    // accidentally 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
   // accidentally 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);
@@ skipping 59 matching lines @@
   // Set to |false| when ShutDownOnIOThread() is called.
   // This is for use with play_on_start_ to track Play() / Pause() state.
   // Must only be touched from the IO thread.
   bool is_started_;
 
   // Data transfer between browser and render process uses a combination
   // of sync sockets and shared memory to provide lowest possible latency.
   // These variables must only be set on the IO thread while the audio_thread_
   // is not running.
   base::SharedMemoryHandle shared_memory_handle_;
-  scoped_ptr<base::CancelableSyncSocket> audio_socket_;
+  scoped_refptr<AudioSocket> audio_socket_;
   int memory_length_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioDevice);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_H_