Revert 232337 "Don't leak a Screen instance in system display AP..."

Causes ChromeOS tests to fail.

> Don't leak a Screen instance in system display API tests.
> 
> BUG=313707
> TBR=hongbo.min@intel.com
> 
> Review URL: https://codereview.chromium.org/54823003

TBR=earthdok@chromium.org

Review URL: https://codereview.chromium.org/55883002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232352 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232352