BUG=libyuv:680
TEST=builds and runs with no warnings

Change-Id: I7d60ef44292fa6ad4f7c4e2e2657359b864d2dab
Reviewed-on: https://chromium-review.googlesource.com/442670
Commit-Queue: Frank Barchard <fbarchard@google.com>
Reviewed-by: Henrik Kjellander <kjellander@chromium.org>