MD Settings: Add helper method for responding to cr.sendWithPromise.

ui/webui/resources/js/cr.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * The global object.
  * @type {!Object}
  * @const
  */
 var global = this;
@@ skipping 313 matching lines @@
   /**
    * The named method the WebUI handler calls directly in response to a
    * chrome.send call that expects a response. The handler requires no knowledge
    * of the specific name of this method, as the name is passed to the handler
    * as the first argument in the arguments list of chrome.send. The handler
    * must pass the ID, also sent via the chrome.send arguments list, as the
    * first argument of the JS invocation; additionally, the handler may
    * supply any number of other arguments that will be included in the response.
    * @param {string} id The unique ID identifying the Promise this response is
    *     tied to.
-   * @param {...*} var_args Variable number of arguments to be included in the
-   *     response.
+   * @param {*} response The response as sent from C++.
    */
-  function webUIResponse(id, var_args) {
+  function webUIResponse(id, response) {
     var resolverFn = chromeSendResolverMap[id];
     delete chromeSendResolverMap[id];
-    // Promise#resolve accepts only one value, therefore wrapping all arguments
-    // passed from C++ to JS in an array.
-    resolverFn(Array.prototype.slice.call(arguments, 1));
+    resolverFn(response);
   }
 
   /**
    * A variation of chrome.send, suitable for messages that expect a single
    * response from C++.
    * @param {string} methodName The name of the WebUI handler API.
    * @param {...*} var_args Varibale number of arguments to be forwarded to the
    *     C++ call.
    * @return {!Promise}
    */
   function sendWithPromise(methodName, var_args) {
     var args = Array.prototype.slice.call(arguments, 1);
     return new Promise(function(resolve, reject) {
       var id = methodName + '_' + createUid();
       chromeSendResolverMap[id] = resolve;
-      chrome.send(methodName, ['cr.webUIResponse', id].concat(args));
+      chrome.send(methodName, [id].concat(args));
     });
   }
 
   /**
    * A registry of callbacks keyed by event name. Used by addWebUIListener to
    * register listeners.
    * @type {!Object<Array<Function>>}
    */
   var webUIListenerMap = Object.create(null);
 
@@ skipping 59 matching lines @@
     get isChromeOS() {
       return /CrOS/.test(navigator.userAgent);
     },
 
     /** Whether this is on vanilla Linux (not chromeOS). */
     get isLinux() {
       return /Linux/.test(navigator.userAgent);
     },
   };
 }();