[Mojo Video Capture] Do not instantiate in-process VideoCaptureSystem when using service

content/browser/renderer_host/media/in_process_video_capture_provider.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_IN_PROCESS_VIDEO_CAPTURE_SYSTEM_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_IN_PROCESS_VIDEO_CAPTURE_SYSTEM_H_
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "content/browser/renderer_host/media/video_capture_provider.h"
 #include "media/capture/video/video_capture_system.h"
 
 namespace content {
 
 class CONTENT_EXPORT InProcessVideoCaptureProvider
     : public VideoCaptureProvider {
  public:
   InProcessVideoCaptureProvider(
       std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
       scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+
   ~InProcessVideoCaptureProvider() override;
 
+  static std::unique_ptr<VideoCaptureProvider>
+  CreateInstanceForNonDeviceCapture(
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+
+  static std::unique_ptr<VideoCaptureProvider> CreateInstance(
+      std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
+      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+
   void Uninitialize() override;
 
   void GetDeviceInfosAsync(
-      const base::Callback<void(
-          const std::vector<media::VideoCaptureDeviceInfo>&)>& result_callback)
-      override;
+      const GetDeviceInfosCallback& result_callback) override;
 
   std::unique_ptr<VideoCaptureDeviceLauncher> CreateDeviceLauncher() override;
 
  private:
+  // Can be nullptr.
   const std::unique_ptr<media::VideoCaptureSystem> video_capture_system_;
   // The message loop of media stream device thread, where VCD's live.
-  scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
+  const scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
+
+  SEQUENCE_CHECKER(sequence_checker_);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_IN_PROCESS_VIDEO_CAPTURE_SYSTEM_H_