Whitelist additional experimental extension for bookmarkManagerPrivate API

BUG=319444
R=kalman@chromium.org

Review URL: https://codereview.chromium.org/73003003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235222 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235222
Added video capture capabilities retrieval and caching to VideoCaptureManager.                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                                
The local cache of video capture names and capabilities is created in a
codepath starting in EnumerateDevices. The cache is update during 
StartCaptureForClient() and StopCaptureForClient(). 
                                                                                                                                                                                                                                                                                
Also added unittests (http://goo.gl/QQbpXW).                                                                                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                
BUG=309554

Review URL: https://codereview.chromium.org/29423003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235223 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235223