Report if video capturing meets output protection requirement.

content/public/browser/media_observer.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_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_
 
 #include "base/callback_forward.h"
 #include "content/public/browser/media_request_state.h"
 #include "content/public/common/media_stream_request.h"
@@ skipping 16 matching lines @@
       int render_frame_id,
       int page_request_id,
       const GURL& security_origin,
       MediaStreamType stream_type,
       MediaRequestState state) = 0;
 
   // Called when an audio stream is being created.
   virtual void OnCreatingAudioStream(int render_process_id,
                                      int render_frame_id) = 0;
 
+  // Called when setting if the video capturing is secure.

[miu, 2016/04/26 01:25:13]

s/if/whether/

I'd suggest expanding this comment a bit more to provide more context. 
Something like: Called when the secure display link status of one or more
consumers of this stream has changed.

[xjz, 2016/04/29 00:11:42]

Done.

+  virtual void OnSetCapturingLinkSecured(int render_process_id,
+                                         int render_frame_id,
+                                         int page_request_id,
+                                         MediaStreamType stream_type,
+                                         bool is_secure) = 0;
+
  protected:
   virtual ~MediaObserver() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_MEDIA_OBSERVER_H_