[Sync] Re-reland fix for bug 154940

Speculatively fixed test by making syncer::UserTypes() stack allocated at
a higher scope, instead of within the for loop. I suspect on certain windows
builds the for loop allocation was being dealloc'd early, hence invalidating
the iterator.

Original codereview at http://codereview.chromium.org/11342022/

BUG=158391
TBR=tim@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11365041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@165521 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed