function set(newModuleManager) {
  asserts.assert(
      moduleManager == null, 'The module manager cannot be redefined.');
  moduleManager = newModuleManager;
  configureFunctions.forEach(configureFn => {
    configureFn(/** @type {!AbstractModuleManager} */ (moduleManager));
  });
  configureFunctions = [];
}
Sets the active module manager. This should never be used to override an
existing manager.

@param {!AbstractModuleManager} newModuleManager