Fix compilation failure with Visual Studio 14.

Change-Id: If009cec928318c90a2f6d445ea8b4b06c4e45209
Reviewed-on: https://chromium-review.googlesource.com/228919
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>