Note that this does not clean up the users of this function, which
may themselves be subject to other overflow issues.
BUG=chromium:728936
Change-Id: I3eaa7627c3b6ff49296ea2618a0157dacdc1d9cc
Reviewed-on: https://skia-review.googlesource.com/29121
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Ben Wagner <bungeman@google.com>