[Mojo Video Capture] Implement a VideoCaptureProvider that uses the video capture service

content/browser/renderer_host/media/in_process_video_capture_provider.cc

 // Copyright 2016 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.
 
 #include "content/browser/renderer_host/media/in_process_video_capture_provider.h"
 
 #include "content/browser/renderer_host/media/in_process_video_capture_device_launcher.h"
 
 namespace content {
 
 InProcessVideoCaptureProvider::InProcessVideoCaptureProvider(
     std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
     scoped_refptr<base::SingleThreadTaskRunner> device_task_runner)
     : video_capture_system_(std::move(video_capture_system)),
       device_task_runner_(std::move(device_task_runner)) {}
 
 InProcessVideoCaptureProvider::~InProcessVideoCaptureProvider() = default;
 
+void InProcessVideoCaptureProvider::Uninitialize() {}
+
 void InProcessVideoCaptureProvider::GetDeviceInfosAsync(
     const base::Callback<void(
         const std::vector<media::VideoCaptureDeviceInfo>&)>& result_callback) {
   // Using Unretained() is safe because |this| owns |video_capture_system_| and
   // |result_callback| has ownership of |this|.
   device_task_runner_->PostTask(
       FROM_HERE, base::Bind(&media::VideoCaptureSystem::GetDeviceInfosAsync,
                             base::Unretained(video_capture_system_.get()),
                             result_callback));
 }
 
 std::unique_ptr<VideoCaptureDeviceLauncher>
 InProcessVideoCaptureProvider::CreateDeviceLauncher() {
   return base::MakeUnique<InProcessVideoCaptureDeviceLauncher>(
       device_task_runner_, video_capture_system_.get());
 }
 
 }  // namespace content