sync: Speculative fix for a possible trigger to bug 48502.  If the user configures data types before the sync backend is initialized, we wind up trying to associate models before a Directory exists, which is badness.
sync: Speculative fix for a possible trigger to bug 48502. 
If the user configures data types before the sync backend is initialized,
we wind up trying to associate models before a Directory exists, which is
badness.

BUG=48502
TEST=none

Review URL: http://codereview.chromium.org/3028013

git-svn-id: http://src.chromium.org/svn/trunk/src@53023 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: c1e3ca16b857afd1e9458cb5bfcbf52bfbb79957
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