Suppress data races introduced by r244074

BUG=333244
TBR=hclam@chromium.org

Review URL: https://codereview.chromium.org/133743003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244173 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244173