code: function getterOrNull(className, property) {
    var ctor = goog.global[className];
    if (!ctor || !ctor.prototype) {
      return null;
    }
    var descriptor = Object.getOwnPropertyDescriptor(ctor.prototype, property);
    return (descriptor && descriptor.get) || null;
  }
docs: Note about browser support:
  - IE 8 and 9 don't have DOM prototypes. There is no simple way of saving
  the methods and accessors for a clobber-safe call.
  - Chrome <43 doesn't have attributes on DOM prototypes, so there is no way of
  making clobber-safe calls for attribute descriptors.
  - IE 8 and 9 don't even have Node and HTMLElement, so there is no
  straightforward way of checking if the result was clobbered for many of the
  methods.
  - IE 8 and 9 have alternate names for getPropertyValue/setProperty in
  CSSStyleDeclaration.
  For simplicity, we don't support IE 8 and 9 for anything but the CSS methods
  which already had IE8 and IE9 support. Chrome 41 must still be supported.
   
  Shorthand for `Object.getOwnPropertyDescriptor(...).get` to improve
  readability during initialization of `Methods`.
  @param {string} className
  @param {string} property
  @return {?Function}