Restrict chrome.bluetooth to the dev channel for M33.
Maybe also M34.

R=kalman@chromium.org

Review URL: https://codereview.chromium.org/135173004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246135 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246135