Site Isolation: RenderView-->RenderFrame for WebContentsVideoCaptureDevice and WebContentsAudioInpu…

content/browser/media/capture/web_contents_video_capture_device.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.
 
 #ifndef CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_
 #define CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 #include "media/video/capture/video_capture_device.h"
 
 namespace content {
 
 class ContentVideoCaptureDeviceCore;
 
 // A virtualized VideoCaptureDevice that mirrors the displayed contents of a
-// tab (accessed via its associated WebContents instance), producing a stream of
-// video frames.
+// WebContents (i.e., the composition of an entire render frame tree), producing
+// a stream of video frames.
 //
 // An instance is created by providing a device_id.  The device_id contains
 // information necessary for finding a WebContents instance.  From then on,
-// WebContentsVideoCaptureDevice will capture from whatever render view is
-// currently associated with that WebContents instance.  This allows the
-// underlying render view to be swapped out (e.g., due to navigation or
-// crashes/reloads), without any interruption in capturing.
-//
-// TODO(miu): In a soon upcoming change, the cross-site isolation migration of
-// this code will be completed such that the main RenderFrameHost is tracked
-// instead of the RenderViewHost.
+// WebContentsVideoCaptureDevice will capture from the RenderWidgetHost that
+// encompasses the currently active RenderFrameHost tree for that that
+// WebContents instance.  As the RenderFrameHost tree mutates (e.g., due to page
+// navigations, or crashes/reloads), capture will continue without interruption.
 class CONTENT_EXPORT WebContentsVideoCaptureDevice
     : public media::VideoCaptureDevice {
  public:
   // Create a WebContentsVideoCaptureDevice instance from the given
   // |device_id|.  Returns NULL if |device_id| is invalid.
   static media::VideoCaptureDevice* Create(const std::string& device_id);
 
   virtual ~WebContentsVideoCaptureDevice();
 
   // VideoCaptureDevice implementation.
   virtual void AllocateAndStart(const media::VideoCaptureParams& params,
                                 scoped_ptr<Client> client) OVERRIDE;
   virtual void StopAndDeAllocate() OVERRIDE;
 
  private:
   WebContentsVideoCaptureDevice(
       int render_process_id, int main_render_frame_id);
 
   const scoped_ptr<ContentVideoCaptureDeviceCore> core_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsVideoCaptureDevice);
 };
 
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_