Suppress two data races in Chromium and a couple of races in libc
BUG=24419,24307
TBR=dank
Review URL: http://codereview.chromium.org/267038

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28566 0039d316-1c4b-4281-b951-d872f2087c98