Remove focusFirstElement as it's never called in current Chrome source

BUG=393873
R=dbeam@chromium.org,khorimoto@chromium.org

Review URL: https://codereview.chromium.org/415863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285791 0039d316-1c4b-4281-b951-d872f2087c98

ui/webui/resources/js/cr/ui/focus_manager.js

@@ -106,13 +106,6 @@ cr.define('cr.ui', function() {
       }
     },
 
-    /**
-     * Attempts to focus the first element in the current dialog.
-     */
-    focusFirstElement: function() {
-      this.focusFirstElement_();
-    },
-
     /**
      * Selects first appropriate focusable element according to the
      * current focus direction and element type.  If it is a radio button,