Report if video capturing meets output protection requirement.

content/public/browser/media_observer.h

Index: content/public/browser/media_observer.h
diff --git a/content/public/browser/media_observer.h b/content/public/browser/media_observer.h
index 6e7088b1c184a299070512db5be73e2e8fdd1e09..66c7ec25a75fbe93743cdb22220dc007a357c3ee 100644
--- a/content/public/browser/media_observer.h
+++ b/content/public/browser/media_observer.h
@@ -34,6 +34,13 @@ class MediaObserver {
   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() {}
 };