Clean up WebSyncProvider now that the browser has implemented the necessary functionality.

BUG=502214

Review URL: https://codereview.chromium.org/1359653002

git-svn-id: svn://svn.chromium.org/blink/trunk/public@202594 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed