Promote methods to register and revoke blob urls to public so they may be used to coin blob urls from within the browser process.

BUG=288015

Review URL: https://codereview.chromium.org/24302005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226064 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226064
Show privet notification checkbox only if privet notifications are enabled

Hide the privet notifications checkbox in chrome://settings/ if privet
notifications are not enabled/available for your platform.

BUG=298384

Review URL: https://codereview.chromium.org/24483006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226065 0039d316-1c4b-4281-b951-d872f2087c98
Makes DesktopCaptureDevice inherit from VideoCaptureDevice and removes unnecessary code.

BUG=297853

Review URL: https://codereview.chromium.org/24522004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226066 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226066