Suppress a leak in xdisplaycheck on CrOS.

BUG=318707
TBR=glider@chromium.org

Review URL: https://codereview.chromium.org/71513003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234809 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234809