Implement a workaround for issue 291207.
BUG=291207
Since chrome doesn't allow us to redirect from cs_oauth_trampoline.js running in the context of the talkgadget page to oauth2_callback.html in the chromoting extension any more, I need to do the redirect manually to unblock browser_tests. This hack will be removed once we make a fix for 291207.
Review URL: https://chromiumcodereview.appspot.com/
23939004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224066 0039d316-1c4b-4281-b951-d872f2087c98