Add DACL and fix test for anonymous read-only memory

      BUG=338538
R=rvargas@chromium.org,brettw@chromium.org
TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/444323005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288152 0039d316-1c4b-4281-b951-d872f2087c98