Pass a DWORD_PTR to SendMessageTimeout in HungWindowDetector::CheckChildWindow

Trivial x64 Windows compile fix.

BUG=166496
TBR=brettw@chromium.org
R=brettw@chromium.org

Review URL: https://chromiumcodereview.appspot.com/12193006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@180323 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed