VideoCaptureDeviceFactory: Change device enumeration to callback + QTKit enumerates in UI thread.

media/video/capture/win/video_capture_device_factory_win.h

 // Copyright 2014 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.
 
 // Implementation of a VideoCaptureDeviceFactory class for Windows platforms.
 
 #ifndef MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_FACTORY_WIN_H_
 #define MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_FACTORY_WIN_H_
 
 #include "media/video/capture/video_capture_device_factory.h"
 
 namespace media {
 
 // Extension of VideoCaptureDeviceFactory to create and manipulate Windows
 // devices, via either DirectShow or MediaFoundation APIs.
 class MEDIA_EXPORT VideoCaptureDeviceFactoryWin :
     public VideoCaptureDeviceFactory {
  public:
   static bool PlatformSupportsMediaFoundation();
 
   VideoCaptureDeviceFactoryWin();
   virtual ~VideoCaptureDeviceFactoryWin() {}
 
   virtual scoped_ptr<VideoCaptureDevice> Create(
-      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
       const VideoCaptureDevice::Name& device_name) OVERRIDE;
   virtual void GetDeviceNames(VideoCaptureDevice::Names* device_names) OVERRIDE;
   virtual void GetDeviceSupportedFormats(
       const VideoCaptureDevice::Name& device,
       VideoCaptureFormats* supported_formats) OVERRIDE;
 
  private:
   bool use_media_foundation_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceFactoryWin);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_FACTORY_WIN_H_