[Mojo Video Capture] Introduce abstraction VideoCaptureSystem

media/capture/video/video_capture_device_factory.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.
 
 #ifndef MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_
 #define MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "media/capture/video/video_capture_device.h"
@@ skipping 18 matching lines @@
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
 
   VideoCaptureDeviceFactory();
   virtual ~VideoCaptureDeviceFactory();
 
   // Creates a VideoCaptureDevice object. Returns NULL if something goes wrong.
   virtual std::unique_ptr<VideoCaptureDevice> CreateDevice(
       const VideoCaptureDeviceDescriptor& device_descriptor) = 0;
 
   // Asynchronous version of GetDeviceDescriptors calling back to |callback|.
+  // TODO(chfremer): Consider removing this if none of the implementations
+  // overrides it. See crbug.com/708233.
   virtual void EnumerateDeviceDescriptors(
       const base::Callback<
           void(std::unique_ptr<VideoCaptureDeviceDescriptors>)>& callback);
 
   // Obtains the supported formats of a device.
   // This method should be called before allocating or starting a device. In
   // case format enumeration is not supported, or there was a problem
   // |supported_formats| will be empty.
   virtual void GetSupportedFormats(
       const VideoCaptureDeviceDescriptor& device_descriptor,
@@ skipping 12 matching lines @@
  private:
   static VideoCaptureDeviceFactory* CreateVideoCaptureDeviceFactory(
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceFactory);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_DEVICE_FACTORY_H_