[Mojo Video Capture] Create abstraction VideoCaptureProvider

content/browser/renderer_host/media/video_capture_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.
 
-// VideoCaptureManager is used to open/close, start/stop, enumerate available
-// video capture devices, and manage VideoCaptureController's.
-// All functions are expected to be called from Browser::IO thread. Some helper
-// functions (*OnDeviceThread) will dispatch operations to the device thread.
-// VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
-// A device can only be opened once.
-
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 
 #include <list>
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/observer_list.h"
 #include "base/process/process_handle.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/elapsed_timer.h"
 #include "build/build_config.h"
-#include "content/browser/renderer_host/media/buildable_video_capture_device.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
+#include "content/browser/renderer_host/media/video_capture_provider.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "media/base/video_facing.h"
 #include "media/capture/video/video_capture_device.h"
 #include "media/capture/video/video_capture_device_info.h"
-#include "media/capture/video/video_capture_system.h"
 #include "media/capture/video_capture_types.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/application_status_listener.h"
 #endif
 
 namespace content {
 class VideoCaptureController;
 class VideoCaptureControllerEventHandler;
 
-// VideoCaptureManager opens/closes and start/stops video capture devices.
+// VideoCaptureManager is used to open/close, start/stop, enumerate available
+// video capture devices, and manage VideoCaptureController's.
+// In its main usage in production, an instance is created by MediaStreamManager
+// on the Browser::IO thread. All public methods are expected to be called from
+// the Browser::IO thread. A device can only be opened once.
 class CONTENT_EXPORT VideoCaptureManager
     : public MediaStreamProvider,
       public BuildableVideoCaptureDevice::Callbacks {
  public:
   using VideoCaptureDevice = media::VideoCaptureDevice;
 
   // Callback used to signal the completion of a controller lookup.
   using DoneCB =
       base::Callback<void(const base::WeakPtr<VideoCaptureController>&)>;
 
-  VideoCaptureManager(
-      std::unique_ptr<media::VideoCaptureSystem> capture_system,
-      scoped_refptr<base::SingleThreadTaskRunner> device_task_runner);
+  explicit VideoCaptureManager(
+      std::unique_ptr<VideoCaptureProvider> video_capture_provider);
 
   // AddVideoCaptureObserver() can be called only before any devices are opened.
   // RemoveAllVideoCaptureObservers() can be called only after all devices
   // are closed.
   // They can be called more than once and it's ok to not call at all if the
   // client is not interested in receiving media::VideoCaptureObserver callacks.
   // This methods can be called on whatever thread. The callbacks of
   // media::VideoCaptureObserver arrive on browser IO thread.
   void AddVideoCaptureObserver(media::VideoCaptureObserver* observer);
   void RemoveAllVideoCaptureObservers();
@@ skipping 188 matching lines @@
 
 #if defined(OS_ANDROID)
   void ReleaseDevices();
   void ResumeDevices();
 
   std::unique_ptr<base::android::ApplicationStatusListener>
       app_status_listener_;
   bool application_state_has_running_activities_;
 #endif
 
-  // The message loop of media stream device thread, where VCD's live.
-  scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;
-
   // Only accessed on Browser::IO thread.
   base::ObserverList<MediaStreamProviderListener> listeners_;
   media::VideoCaptureSessionId new_capture_session_id_;
 
   // An entry is kept in this map for every session that has been created via
   // the Open() entry point. The keys are session_id's. This map is used to
   // determine which device to use when ConnectClient() occurs. Used
   // only on the IO thread.
   SessionMap sessions_;
 
   // Currently opened VideoCaptureController instances. The device may or may
   // not be started. This member is only accessed on IO thread.
   std::vector<scoped_refptr<VideoCaptureController>> controllers_;
 
   // TODO(chfremer): Consider using CancellableTaskTracker, see
   // crbug.com/598465.
   DeviceStartQueue device_start_request_queue_;
 
   // Queue to keep photo-associated requests waiting for a device to initialize,
   // bundles a session id integer and an associated photo-related request.
   std::list<std::pair<int, base::Closure>> photo_request_queue_;
 
-  // Device creation factory injected on construction from MediaStreamManager or
-  // from the test harness.
-  std::unique_ptr<media::VideoCaptureSystem> video_capture_system_;
+  const std::unique_ptr<VideoCaptureProvider> video_capture_provider_;
 
   base::ObserverList<media::VideoCaptureObserver> capture_observers_;
 
   // Local cache of the enumerated DeviceInfos. GetDeviceSupportedFormats() will
   // use this list if the device is not started, otherwise it will retrieve the
   // active device capture format from the VideoCaptureController associated.
   std::vector<media::VideoCaptureDeviceInfo> devices_info_cache_;
 
   // Map used by DesktopCapture.
   std::map<media::VideoCaptureSessionId, gfx::NativeViewId>
       notification_window_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_