This is the followup we need to do after #6406 to remove dead code.

/**
   * Inject some specialized knowledge about the DOM. This takes a config object
   * with the following properties:
   *
   * isCustomAttribute: function that given an attribute name will return true
   * if it can be inserted into the DOM verbatim. Useful for data-* or aria-*
   * attributes where it's impossible to enumerate all of the possible
   * attribute names,
   *
   * Properties: object mapping DOM property name to one of the
   * DOMPropertyInjection constants or null. If your attribute isn't in here,
   * it won't get written to the DOM.
   *
   * DOMAttributeNames: object mapping React attribute name to the DOM
   * attribute name. Attribute names not specified use the **lowercase**
   * normalized name.
   *
   * DOMAttributeNamespaces: object mapping React attribute name to the DOM
   * attribute namespace URL. (Attribute names not specified use no namespace.)
   *
   * DOMPropertyNames: similar to DOMAttributeNames but for DOM properties.
   * Property names not specified use the normalized name.
   *
   * DOMMutationMethods: Properties that require special mutation methods. If
   * `value` is undefined, the mutation method should unset the property.
   *
   * @param {object} domPropertyConfig the config as described above.
   */
  injectDOMPropertyConfig: function(domPropertyConfig) {
    var Injection = DOMPropertyInjection;