message: give the component update computation a name
diff: @@ -61,7 +61,7 @@ export function lifecycleMixin (Vue: Class<Component>) {
  }
  }
  callHook(vm, 'beforeMount')
  - vm._watcher = new Watcher(vm, () => {
  + vm._watcher = new Watcher(vm, function updateComponent () {
  vm._update(vm._render(), hydrating)
  }, noop)
  hydrating = false
  