code: function getOrCreateChangeDetectorRef(di, context) {
      if (di.changeDetectorRef)
          return di.changeDetectorRef;
      var currentNode = di.node;
      if (isComponent(currentNode.tNode)) {
          return di.changeDetectorRef = new ViewRef$1(currentNode.data, context);
      }
      else if (currentNode.tNode.type === 3 /* Element */) {
          return di.changeDetectorRef = getOrCreateHostChangeDetector(currentNode.view[HOST_NODE]);
      }
      return null;
  }
docs: Creates a ViewRef and stores it on the injector as ChangeDetectorRef (public alias).
  Or, if it already exists, retrieves the existing instance.
  
  @returns The ChangeDetectorRef to use