[MD Extensions] Include the manifest code snippet in load errors

chrome/test/data/webui/extensions/extension_code_section_test.js

 // Copyright 2016 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 Suite of tests for extensions-code-section. */
 cr.define('extension_code_section_tests', function() {
   /** @enum {string} */
   var TestNames = {
     Layout: 'layout',
   };
 
   function registerTests() {
     suite('ExtensionCodeSectionTest', function() {
       /** @type {chrome.developerPrivate.RequestFileSourceResponse} */
       var code = {
         beforeHighlight: 'this part before the highlight\nAnd this too\n',
         highlight: 'highlight this part\n',
         afterHighlight: 'this part after the highlight\n',
         message: 'Highlight message',
       };
 
       /** @type {extensions.CodeSection} */
       var codeSection;
 
-      var noCodeError = 'No code here';
+      var couldNotDisplayCode = 'No code here';
 
       suiteSetup(function() {
         return PolymerTest.importHtml('chrome://extensions/code_section.html');
       });
 
       // Initialize an extension item before each test.
       setup(function() {
         PolymerTest.clearBody();
         codeSection = new extensions.CodeSection();
-        codeSection.noCodeError = noCodeError;
+        codeSection.couldNotDisplayCode = couldNotDisplayCode;
         document.body.appendChild(codeSection);
       });
 
       test(assert(TestNames.Layout), function() {
         Polymer.dom.flush();
 
         var testIsVisible =
             extension_test_util.isVisible.bind(null, codeSection);
         expectFalse(!!codeSection.code);
-        expectTrue(codeSection.isMainHidden_());
+        expectTrue(codeSection.isEmpty());
         expectTrue(codeSection.$$('#main').hidden);
         expectFalse(testIsVisible('#main'));
         expectTrue(testIsVisible('#no-code'));
         expectEquals('', codeSection.$['line-numbers'].textContent.trim());
 
         codeSection.code = code;
         expectTrue(testIsVisible('#main'));
         expectFalse(testIsVisible('#no-code'));
 
         var fullSpan = codeSection.$$('#source span');
         expectEquals(
             code.beforeHighlight + code.highlight + code.afterHighlight,
             fullSpan.textContent);
         var highlightSpan = codeSection.$$('.highlight');
         expectEquals(code.highlight, highlightSpan.textContent);
         expectEquals(code.message, highlightSpan.title);
         expectEquals('1\n2\n3\n4',
                      codeSection.$['line-numbers'].textContent.trim());
       });
     });
   }
 
   return {
     registerTests: registerTests,
     TestNames: TestNames,
   };
 });