code: function _handleKeyEvent(event) {
          var i, handled = false;
          for (i = _globalKeydownHooks.length - 1; i >= 0; i--) {
              if (_globalKeydownHooks[i](event)) {
                  handled = true;
                  break;
              }
          }
          _detectAltGrKeyDown(event);
          if (!handled && _handleKey(_translateKeyboardEvent(event))) {
              event.stopPropagation();
              event.preventDefault();
          }
      }
docs: Handles a given keydown event, checking global hooks first before
  deciding to handle it ourselves.
  @param {Event} The keydown event to handle.