code: function ValueMirror(type, value, transient) {
    %_Call(Mirror, this, type);
    this.value_ = value;
    if (!transient) {
      this.allocateHandle_();
    } else {
      this.allocateTransientHandle_();
    }
  }
docs: Base class for all value mirror objects.
  @param {string} type The type of the mirror
  @param {value} value The value reflected by this mirror
  @param {boolean} transient indicate whether this object is transient with a
  transient handle
  @constructor
  @extends Mirror