Add support for switching the audio output device for HTMLMediaElements.

media/audio/audio_output_ipc.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.
 
 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
 
+#include <string>
+
+#include "base/callback.h"
 #include "base/memory/shared_memory.h"
 #include "base/sync_socket.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/media_export.h"
+#include "url/gurl.h"
 
 namespace media {
 
 // Contains IPC notifications for the state of the server side
 // (AudioOutputController) audio state changes and when an AudioOutputController
 // has been created.  Implemented by AudioOutputDevice.
 class MEDIA_EXPORT AudioOutputIPCDelegate {
  public:
   // Current status of the audio output stream in the browser process. Browser
   // sends information about the current playback state and error to the
   // renderer process using this type.
   enum State {
     kPlaying,
     kPaused,
     kError,
     kStateLast = kError
   };
 
+  // Result of an audio output device switch operation
+  enum DeviceSwitchResult {
+    kSuccess = 0,
+    kNotFound,
+    kSecurityError,
+    kOtherError,
+    kDeviceSwitchResultLast = kOtherError
+  };
+
+
   // Called when state of an audio stream has changed.
   virtual void OnStateChanged(State state) = 0;
 
   // Called when an audio stream has been created.
   // The shared memory |handle| points to a memory section that's used to
   // transfer audio buffers from the AudioOutputIPCDelegate back to the
   // AudioRendererHost.  The implementation of OnStreamCreated takes ownership.
   // The |socket_handle| is used by AudioRendererHost to signal requests for
   // audio data to be written into the shared memory. The AudioOutputIPCDelegate
   // must read from this socket and provide audio whenever data (search for
   // "pending_bytes") is received.
   virtual void OnStreamCreated(base::SharedMemoryHandle handle,
                                base::SyncSocket::Handle socket_handle,
                                int length) = 0;
 
+  // Called when an attempt to switch the output device has been completed
+  virtual void OnDeviceSwitched(int request_id, DeviceSwitchResult result) = 0;
+
   // Called when the AudioOutputIPC object is going away and/or when the IPC
   // channel has been closed and no more ipc requests can be made.
   // Implementations should delete their owned AudioOutputIPC instance
   // immediately.
   virtual void OnIPCClosed() = 0;
 
  protected:
   virtual ~AudioOutputIPCDelegate();
 };
 
@@ skipping 22 matching lines @@
   // Pauses an audio stream.  This should generate a call to
   // AudioOutputController::Pause().
   virtual void PauseStream() = 0;
 
   // Closes the audio stream which should shut down the corresponding
   // AudioOutputController in the peer process.
   virtual void CloseStream() = 0;
 
   // Sets the volume of the audio stream.
   virtual void SetVolume(double volume) = 0;
+
+  // Switches the output device of the audio stream. This should generate a
+  // call to AudioOutputController::SwitchOutputDevice().
+  virtual void SwitchDevice(const std::string& device_id,
+                            const GURL& security_origin,
+                            int request_id,
+                            const base::Callback<void(int)>& callback) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_