suppress leak in gcm code

BUG=321975
TBR=jianli@chromium.org

Review URL: https://codereview.chromium.org/80783002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236493 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236493