Fixes bug in tab dragging when rtl where the dragged tab was incorrectly positioned.
Fixes bug in tab dragging when rtl where the dragged tab was
incorrectly positioned.

BUG=51219
TEST=see bug

Review URL: http://codereview.chromium.org/3091008

git-svn-id: http://src.chromium.org/svn/trunk/src@55067 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: bb633a5ca3c23265dc173688161a619942ef8f2f
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