Re-land 64094 - Mac: turn on file access checks for the UI thread.

BUG=60211
TEST=bots

Review URL: http://codereview.chromium.org/4144003

TBR=thakis@chromium.org
Review URL: http://codereview.chromium.org/4208001

TBR=nick@chromium.org
Review URL: http://codereview.chromium.org/4139005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64152 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed