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

chrome/test/data/webui/webui_resource_async_browsertest.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview Framework for running async JS tests for cr.js utility methods.
  */
 
 /** @const {string} Path to source root. */
 var ROOT_PATH = '../../../../';
@@ skipping 38 matching lines @@
   function whenChromeSendCalled(name) {
     return new Promise(function(resolve, reject) {
       registerMessageCallback(name, null, resolve);
     });
   }
 
   suite('cr.js', function() {
     setup(function() {
       // Simulate a WebUI handler that echoes back all parameters passed to it.
       whenChromeSendCalled(CHROME_SEND_NAME).then(function(args) {
-        assertEquals('cr.webUIResponse', args[0]);
-        var globalCallbackArgs = args.slice(1);
-        cr.webUIResponse.apply(null, globalCallbackArgs);
+        cr.webUIResponse.apply(null, args);
       });
     });
 
-    test('sendWithPromise_MultipleArgs', function() {
-      return cr.sendWithPromise(CHROME_SEND_NAME, 'foo', 'bar').then(
+    test('sendWithPromise_ResponseObject', function() {
+      var expectedResponse = {'foo': 'bar'};
+      return cr.sendWithPromise(CHROME_SEND_NAME, expectedResponse).then(
           function(response) {
-            assertEquals(['foo', 'bar'].join(), response.join());
+            assertEquals(
+                JSON.stringify(expectedResponse), JSON.stringify(response));
           });
     });
 
-    test('sendWithPromise_NoArgs', function() {
+    test('sendWithPromise_ResponseArray', function() {
+      var expectedResponse = ['foo', 'bar'];
+      return cr.sendWithPromise(CHROME_SEND_NAME, expectedResponse).then(
+          function(response) {
+            assertEquals(
+                JSON.stringify(expectedResponse), JSON.stringify(response));
+          });
+    });
+
+    test('sendWithPromise_ResponsePrimitive', function() {
+      var expectedResponse = 1234;
+      return cr.sendWithPromise(CHROME_SEND_NAME, expectedResponse).then(
+          function(response) {
+            assertEquals(expectedResponse, response);
+          });
+    });
+
+    test('sendWithPromise_ResponseVoid', function() {
       return cr.sendWithPromise(CHROME_SEND_NAME).then(function(response) {
-        assertEquals([].join(), response.join());
+        assertEquals(undefined, response);
       });
     });
   });
 
   // Run all registered tests.
   mocha.run();
 });