Fix crash on older versions of windows that don't have DWM APIs.
Fix crash on older versions of windows that don't have DWM APIs.

http://crbug.com/17290
TEST=none

Review URL: http://codereview.chromium.org/155798

git-svn-id: http://src.chromium.org/svn/trunk/src@21112 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: f275f3fc3e65597c9d558b940aceae5a5f1a9f95
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser