Fixes bug in TabStrip where dragging tab out then back in rapidly could cause the tabstrip to get out of sync with the model.
Fixes bug in TabStrip where dragging tab out then back in rapidly
could cause the tabstrip to get out of sync with the model.

BUG=40714
TEST=thorougly test dragging tabs around in tab strip.

Review URL: http://codereview.chromium.org/1556020

git-svn-id: http://src.chromium.org/svn/trunk/src@43954 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 9b9261b3865e081de211fc2f0a4b12102d5a8ea5
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