[MD History] Add routing for synced devices page.

chrome/browser/resources/md_history/app.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.
 
 Polymer({
   is: 'history-app',
 
   properties: {
     // The id of the currently selected page.
     selectedPage: {
       type: String,
       value: 'history-list'
+    },
+    route: {
+      type: Object
+    },
+    routeData: {
+      type: Object,
+      observer: 'routeChanged_'
     }
   },
 
   // TODO(calamity): Replace these event listeners with data bound properties.
   listeners: {
     'history-checkbox-select': 'checkboxSelected',
     'unselect-all': 'unselectAll',
     'delete-selected': 'deleteSelected',
     'search-changed': 'searchChanged',
   },
 
+  routeChanged_: function() {
+    console.log(this.routeData.page);
+    var routeToElementId = {
+      'openTabs': 'history-synced-device-manager',
+    };
+    var path = this.routeData.page;
+    var elementId =
+        routeToElementId[path] ? routeToElementId[path] : 'history-list';
+    this.$['content'].selected = elementId;
+  },
+
   /**
    * Listens for history-item being selected or deselected (through checkbox)
    * and changes the view of the top toolbar.
    * @param {{detail: {countAddition: number}}} e
    */
   checkboxSelected: function(e) {
     var toolbar = /** @type {HistoryToolbarElement} */(this.$.toolbar);
     toolbar.count += e.detail.countAddition;
   },
 
@@ skipping 53 matching lines @@
   },
 
   /**
    * @param {!Array<!ForeignSession>} sessionList Array of objects describing
    *     the sessions from other devices.
    * @param {boolean} isTabSyncEnabled Is tab sync enabled for this profile?
    */
   setForeignSessions: function(sessionList, isTabSyncEnabled) {
     // TODO(calamity): Add a 'no synced devices' message when sessions are
     // empty.
-    this.$['history-side-bar'].hidden = !isTabSyncEnabled;
     var syncedDeviceElem = this.$['history-synced-device-manager'];
     var syncedDeviceManager =
         /** @type {HistorySyncedDeviceManagerElement} */(syncedDeviceElem);
     if (isTabSyncEnabled) {
       syncedDeviceManager.setSyncedHistory(sessionList);
       /** @type {HistoryToolbarElement} */(this.$.toolbar).hasSidebar = true;
     }
   },
 
   deleteComplete: function() {
     var historyList = /** @type {HistoryListElement} */(this.$['history-list']);
     var toolbar = /** @type {HistoryToolbarElement} */(this.$.toolbar);
     historyList.removeDeletedHistory(toolbar.count);
     toolbar.count = 0;
   }
 });