Add an LSan suppression for a leak in xrandr.

BUG=119677
TBR=timurrrr@chromium.org

Review URL: https://codereview.chromium.org/62203009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233878 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233878