function taintDataProperty(obj, property) {
  Object.defineProperty(obj, property, {
    set: function(value) {
      $ERROR("Client code can adversely affect behavior: setter for " + property + ".");
    },
    enumerable: false,
    configurable: true
  });
}
Taints a named data property of the given object by installing
a setter that throws an exception.
@param {object} obj the object whose data property to taint
@param {string} property the property to taint