[Mojo Video Capture] Add content_browsertest for exercising video capture

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.
@@ skipping 50 matching lines @@
   // 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();
 
   // Implements MediaStreamProvider.
   void RegisterListener(MediaStreamProviderListener* listener) override;
-  void UnregisterListener() override;
-  int Open(const StreamDeviceInfo& device) override;
+  void UnregisterListener(MediaStreamProviderListener* listener) override;
+  int Open(const MediaStreamDevice& device) override;
   void Close(int capture_session_id) override;
 
   // Called by VideoCaptureHost to locate a capture device for |capture_params|,
   // adding the Host as a client of the device's controller if successful. The
   // value of |session_id| controls which device is selected;
   // this value should be a session id previously returned by Open().
   //
   // If the device is not already started (i.e., no other client is currently
   // capturing from this device), this call will cause a VideoCaptureController
   // and VideoCaptureDevice to be created, possibly asynchronously.
   //
   // On success, the controller is returned via calling |done_cb|, indicating
   // that the client was successfully added. A NULL controller is passed to
-  // the callback on failure.
+  // the callback on failure. |done_cb| is not allowed to synchronously call
+  // StopCaptureForClient().
   void StartCaptureForClient(media::VideoCaptureSessionId session_id,
                              const media::VideoCaptureParams& capture_params,
                              VideoCaptureControllerID client_id,
                              VideoCaptureControllerEventHandler* client_handler,
                              const DoneCB& done_cb);
 
   // Called by VideoCaptureHost to remove |client_handler|. If this is the last
   // client of the device, the |controller| and its VideoCaptureDevice may be
   // destroyed. The client must not access |controller| after calling this
   // function.
@@ skipping 222 matching lines @@
 
   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.
-  MediaStreamProviderListener* listener_;
+  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 StartCaptureForClient() occurs. Used
   // only on the IO thread.
   SessionMap sessions_;
 
   // Currently opened DeviceEntry instances (each owning a VideoCaptureDevice -
   // VideoCaptureController pair). The device may or may not be started. This
@@ skipping 26 matching lines @@
   // 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_