Suppress races in DesktopMediaListTest.UpdateTitle

BUG=342662
TBR=jiayl@chromium.org

Review URL: https://codereview.chromium.org/140093012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250416 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250416