Valgrind suppression for sync leak.
Valgrind suppression for sync leak.

BUG=56090
TEST=None
TBR=tim

git-svn-id: http://src.chromium.org/svn/trunk/src@59892 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: d36916b79caf1c17b55454d5f81979896e768bad
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