Fix a typo in documentation.

Change-Id: Ibbde1b31fdeade51caf0cb70fefbe915bd7a9af6
Reviewed-on: https://chromium-review.googlesource.com/1169693
Commit-Queue: Eric Roman <eroman@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582376}
1 file changed