Add database model worker to worker registry and remove deprecated thread check.
Add database model worker to worker registry and remove deprecated thread
check.

BUG=29926
TEST=Attempt to sync Autofill with a dev server.

Review URL: http://codereview.chromium.org/660343

git-svn-id: http://src.chromium.org/svn/trunk/src@40341 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 9d770f5a39069aa6053c50972c0735c52706d78e
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser