GitLab

* StopEventsPropagation should check window visibility.
* Changed IsScreenLocked to use the same logic as 
  CanFocus.

BUG=none
TEST=new test case is added to window_unittests.cc

Review URL: http://codereview.chromium.org/9181012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117600 0039d316-1c4b-4281-b951-d872f2087c98