getKeyDefAction = (name) => {
    // Get the key action for the given action name.  If the action is a
    // function, dispatch it.  If the action defers to the normal action,
    // resolve that instead.

    resolvedActionType = name;

    let action = keyDef[name];
    if (typeof action == 'function') {
      action = action.call(this.keyMap, e, keyDef);
    }

    if (action === DEFAULT && name != 'normal') {
      action = getKeyDefAction('normal');
    }

    return action;
  }
Get the default key definition action for the given modifier name.

@param {string} name 'control', 'alt', 'meta', or 'normal'.
@return {!hterm.Keyboard.KeyDefAction}