Services that would listen for password change in MU/Supervisor sessions.

BUG=244472
TBR=noms@chromium.org

Review URL: https://codereview.chromium.org/142693004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249386 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249386
Use constant for invalid request_id in EmbeddedWorker messaging

BUG=313530
TEST=existing EW tests should pass

Review URL: https://codereview.chromium.org/149673005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249387 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249387