message: fix(decal): update weakmap
diff: -let wmUniqueIndex = 0;
  +let wmUniqueIndex = Math.round(Math.random() * 9);
  export default class WeakMap<K extends object, V> {
  protected _id: string;
  constructor() {
  - this._id = '__\0ec_wm_' + wmUniqueIndex++ + '_' + Math.random().toFixed(5);
  + this._id = '__ec_inner_' + wmUniqueIndex++;
  }
  get(key: K): V {
  @@ -13,7 +13,17 @@ export default class WeakMap<K extends object, V> {
  }
  set(key: K, value: V): WeakMap<K, V> {
  - (this._guard(key) as any)[this._id] = value;
  + const target = this._guard(key) as any;
  + if (typeof Object.defineProperty === 'function') {
  + Object.defineProperty(target, this._id, {
  + value: value,
  + enumerable: false,
  + configurable: false
  + });
  + }
  + else {
  + target[this._id] = value;
  + }
  return this;
  }
  