GitLab

Stop using browser signin for passphrase migration, just use the normal signin flow which is accessible from all parts of the sync UI.  Create the correct state transition from login -> initial passphrase selection.

BUG=70429
TEST=upgrade a sync-everything profile to latest chrome

Review URL: http://codereview.chromium.org/6357011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72236 0039d316-1c4b-4281-b951-d872f2087c98