Function makeComputedGetter

06.Router/basic/js/vue.js:8026–8039

(getter, owner)

    };

    function makeComputedGetter(getter, owner) {
      var watcher = new Watcher(owner, getter, null, {
        lazy: true
      });
      return function computedGetter() {
        if (watcher.dirty) {
          watcher.evaluate();
        }
        if (Dep.target) {
          watcher.depend();
        }
        return watcher.value;
      };
    }

    /**
     * Setup instance methods. Methods must be bound to the