[Build Fix] Add missing #include

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/84533002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236956 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236956