Makes creating a window in ash work outside of metro

Without this we crash as ActiveMetroChrome makes no sense outside of
chrome.

BUG=none
TEST=none
R=ananta@chromium.org

Review URL: https://codereview.chromium.org/146393003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249255 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249255