message: Manually compositing when having incremental rendering on a canvas root.
diff: @@ -54,6 +54,15 @@ IncrementalDisplayble.prototype.addDisplayables = function (displayables, notPer
  }
  };
  +IncrementalDisplayble.prototype.eachPendingDisplayable = function (cb) {
  + for (var i = this._cursor; i < this._displayables.length; i++) {
  + cb && cb(this._displayables[i]);
  + }
  + for (var i = 0; i < this._temporaryDisplayables.length; i++) {
  + cb && cb(this._temporaryDisplayables[i]);
  + }
  +};
  +
  IncrementalDisplayble.prototype.update = function () {
  this.updateTransform();
  for (var i = this._cursor; i < this._displayables.length; i++) {
  