Invoke the CF migration path when applying a CF multi update. 

Moves MigrateChromeFrame (without changing its logic) from setup_main.cc
into cf_migration.cc.

Contributed by robertshield@chromium.org (originally from
https://codereview.chromium.org/22632009/).

BUG=265952
TEST=A multi Chrome Frame install receiving an update will change to a SxS Chrome Frame install. And will still work.

Review URL: https://chromiumcodereview.appspot.com/24287006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224600 0039d316-1c4b-4281-b951-d872f2087c98
Add a static function to enable/disable MediaDrmBridge

BUG=233420

Review URL: https://chromiumcodereview.appspot.com/24307002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224601 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224601