Suppress valgrind failure on mac ui tests, where callback is being invoked on freed object.
Suppress valgrind failure on mac ui tests, where callback is being invoked on freed object.

BUG=52387
TBR=mpcomplete
Review URL: http://codereview.chromium.org/3181017

git-svn-id: http://src.chromium.org/svn/trunk/src@56301 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: f05654b6fe307e08f5fbc4320f1cc3f072c004ec
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