Rmoving the notion of task runner from MediaStreamProvider interface.

content/browser/renderer_host/media/audio_input_device_manager.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.
 //
 // AudioInputDeviceManager manages the audio input devices. In particular it
 // communicates with MediaStreamManager and AudioInputRendererHost on the
 // browser IO thread, handles queries like
 // enumerate/open/close/GetOpenedDeviceInfoById from MediaStreamManager and
 // GetOpenedDeviceInfoById from AudioInputRendererHost.
 // The work for enumerate/open/close is handled asynchronously on Media Stream
@@ skipping 13 matching lines @@
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/common/media_stream_request.h"
 
 namespace media {
 class AudioManager;
 }
 
 namespace content {
 
+// Should be used on IO thread only.
 class CONTENT_EXPORT AudioInputDeviceManager : public MediaStreamProvider {
  public:
   // Calling Start() with this kFakeOpenSessionId will open the default device,
   // even though Open() has not been called. This is used to be able to use the
   // AudioInputDeviceManager before MediaStream is implemented.
   // TODO(xians): Remove it when the webrtc unittest does not need it any more.
   static const int kFakeOpenSessionId;
 
   explicit AudioInputDeviceManager(media::AudioManager* audio_manager);
 
   // Gets the opened device info by |session_id|. Returns NULL if the device
   // is not opened, otherwise the opened device. Called on IO thread.
   const StreamDeviceInfo* GetOpenedDeviceInfoById(int session_id);
 
-  void Unregister();
-
-  // MediaStreamProvider implementation, called on IO thread.
-  void Register(MediaStreamProviderListener* listener,
-                const scoped_refptr<base::SingleThreadTaskRunner>&
-                    device_task_runner) override;
+  // MediaStreamProvider implementation.
+  void RegisterListener(MediaStreamProviderListener* listener) override;
+  void UnregisterListener() override;
   int Open(const StreamDeviceInfo& device) override;
   void Close(int session_id) override;
 
 #if defined(OS_CHROMEOS)
   // Registers and unregisters that a stream using keyboard mic has been opened
   // or closed. Keeps count of how many such streams are open and activates and
   // inactivates the keyboard mic accordingly. The (in)activation is done on the
   // UI thread and for the register case a callback must therefor be provided
   // which is called when activated.
-  // Called on the IO thread.
   void RegisterKeyboardMicStream(const base::Closure& callback);
   void UnregisterKeyboardMicStream();
 #endif
 
  private:
   typedef std::vector<StreamDeviceInfo> StreamDeviceList;
   ~AudioInputDeviceManager() override;
 
   // Opens the device on media stream device thread.
   void OpenOnDeviceThread(int session_id, const StreamDeviceInfo& info);
@@ skipping 31 matching lines @@
 
   // The message loop of media stream device thread that this object runs on.
   scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioInputDeviceManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_H_