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

chrome/browser/resources/media_router/elements/issue_banner/issue_banner.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.
 
 // This Polymer element is used to show information about issues related
 // to casting.
 Polymer({
   is: 'issue-banner',
 
   properties: {
     /**
-     * The current view to be shown.
-     * @private {media_router.MediaRouterView}
-     */
-    currentView_: {
-      type: String,
-      readOnly: true,
-      value: media_router.MediaRouterView.ISSUE,
-    },
-
-    /**
      * The text shown in the default action button.
      * @private {string}
      */
     defaultActionButtonText_: {
       type: String,
       value: '',
     },
 
     /**
-     * The header text.
-     * @private {string}
-     */
-    headerText_: {
-      type: String,
-      readOnly: true,
-      value: loadTimeData.getString('issueHeader'),
-    },
-
-    /**
      * The issue to show.
      * @type {?media_router.Issue}
      */
     issue: {
       type: Object,
       value: null,
       observer: 'updateActionButtonText_',
     },
 
     /**
@@ skipping 105 matching lines @@
         secondaryText = loadTimeData.getString(
             this.issueActionTypeToButtonTextResource_[
             this.issue.secondaryActionType]);
       }
     }
 
     this.defaultActionButtonText_ = defaultText;
     this.secondaryActionButtonText_ = secondaryText;
   },
 });