Compilation warnings on clang.

This reverts commit 18cc14b5.

Change-Id: If58047486116e34ef30c4b317d3fb47cd2349d15
Reviewed-on: https://chromium-review.googlesource.com/319822Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>