[Media Router] Use common media-router-header for MR UI.

chrome/test/data/webui/media_router/issue_banner_tests.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 Suite of tests for issue-banner. */
 cr.define('issue_banner', function() {
   function registerTests() {
     suite('IssueBanner', function() {
       /**
        * Issue Banner created before each test.
@@ skipping 168 matching lines @@
         banner.issue = fakeNonBlockingIssueOne;
         checkIssueText(banner.issue);
       });
 
       // Tests whether parts of the issue-banner is hidden based on the
       // current state.
       test('hidden versus visible components', function() {
         // The blocking UI should be shown along with an optional action.
         banner.issue = fakeBlockingIssueOne;
         checkButtonVisibility(fakeBlockingIssueOne.secondaryActionType);
-        assertFalse(banner.$['issue-header'].hasAttribute('hidden'));
 
         // The blocking UI should be shown without an optional action.
         banner.issue = fakeBlockingIssueTwo;
         checkButtonVisibility(fakeBlockingIssueTwo.secondaryActionType);
-        assertFalse(banner.$['issue-header'].hasAttribute('hidden'));
 
         // The non-blocking UI should be shown along with an optional action.
         banner.issue = fakeNonBlockingIssueOne;
         checkButtonVisibility(fakeNonBlockingIssueOne.secondaryActionType);
-        assertTrue(banner.$['issue-header'].hasAttribute('hidden'));
 
         // The non-blocking UI should be shown without an optional action.
         banner.issue = fakeNonBlockingIssueTwo;
         checkButtonVisibility(fakeNonBlockingIssueTwo.secondaryActionType);
-        assertTrue(banner.$['issue-header'].hasAttribute('hidden'));
       });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });