enable video capture to support sharing across multiple renderer processes

content/browser/renderer_host/media/video_capture_host.h

 // Copyright (c) 2011 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.
 //
 // VideoCaptureHost serves video capture related messages from
 // VideCaptureMessageFilter which lives inside the render process.
 //
 // This class is owned by BrowserRenderProcessHost, and instantiated on UI
 // thread, but all other operations and method calls happen on IO thread.
 //
@@ skipping 70 matching lines @@
   friend class VideoCaptureHostTest;
 
   virtual ~VideoCaptureHost();
 
   // IPC message: Start capture on the VideoCaptureDevice referenced by
   // VideoCaptureParams::session_id. |device_id| is an id created by
   // VideCaptureMessageFilter to identify a session
   // between a VideCaptureMessageFilter and a VideoCaptureHost.
   void OnStartCapture(int device_id,
                       const media::VideoCaptureParams& params);
+  void OnControllerAdded(
+      int device_id, const media::VideoCaptureParams& params,
+      VideoCaptureController* controller);
+  void DoControllerAddedOnIOThreead(
+      int device_id, const media::VideoCaptureParams params,
+      VideoCaptureController* controller);
 
   // IPC message: Stop capture on device referenced by |device_id|.
   void OnStopCapture(int device_id);
 
   // IPC message: Pause capture on device referenced by |device_id|.
   void OnPauseCapture(int device_id);
 
   // IPC message: Receive an empty buffer from renderer. Send it to device
   // referenced by |device_id|.
   void OnReceiveEmptyBuffer(int device_id, int buffer_id);
@@ skipping 17 matching lines @@
   // Send a information about frame resolution and frame rate
   // to the VideoCaptureMessageFilter.
   void DoSendFrameInfo(int device_id,
                        int width,
                        int height,
                        int frame_per_second);
 
   // Handle error coming from VideoCaptureDevice.
   void DoHandleError(int device_id);
 
+  // Helpers.
+  media_stream::VideoCaptureManager* GetVideoCaptureManager();
+
   typedef std::map<VideoCaptureControllerID,
-                   scoped_refptr<VideoCaptureController> >EntryMap;
-
+                   scoped_refptr<VideoCaptureController> > EntryMap;
   // A map of VideoCaptureControllerID to VideoCaptureController
   // objects that is currently active.
   EntryMap entries_;
 
+  typedef std::map<VideoCaptureControllerID,
+                   media::VideoCapture::State> EntryState;
+  // Record state of each VideoCaptureControllerID.
+  EntryState entry_state_;
+
   // Used to get a pointer to VideoCaptureManager to start/stop capture devices.
   const content::ResourceContext* resource_context_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_HOST_H_