Mac: Add AssertIOAllowed() call to CopyFile()

BUG=60211
TEST=trybots

Review URL: http://codereview.chromium.org/4133005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64309 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed