Chromecast buildfix: forgot an include.

Was necessary for https://codereview.chromium.org/517213005/.

R=lcwu@chromium.org,damienv@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/526693002

Cr-Commit-Position: refs/heads/master@{#292804}
1 file changed