[Sync] Removing complexity around PROXY_TABS now that empty sessions are provided when disabled.

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.
 
 cr.define('md_history', function() {
   var lazyLoadPromise = null;
   function ensureLazyLoaded() {
     if (!lazyLoadPromise) {
       lazyLoadPromise = new Promise(function(resolve, reject) {
         Polymer.Base.importHref(
@@ skipping 248 matching lines @@
       this.focusToolbarSearchField();
     if (e.command.id == 'delete-command')
       this.deleteSelected();
     if (e.command.id == 'toggle-grouped')
       this.grouped_ = !this.grouped_;
   },
 
   /**
    * @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) {
-    if (!isTabSyncEnabled) {
-      var syncedDeviceManagerElem =
-      /** @type {HistorySyncedDeviceManagerElement} */this
-          .$$('history-synced-device-manager');
-      if (syncedDeviceManagerElem) {
-        md_history.ensureLazyLoaded().then(function() {
-          syncedDeviceManagerElem.tabSyncDisabled();
-        });
-      }
-      return;
-    }
-
+  setForeignSessions: function(sessionList) {
     this.set('queryResult_.sessionList', sessionList);
   },
 
   /**
    * Called when browsing data is cleared.
    */
   historyDeleted: function() {
     this.$.history.historyDeleted();
   },
 
@@ skipping 103 matching lines @@
             break;
         }
         break;
     }
 
     md_history.BrowserService.getInstance().recordHistogram(
       'History.HistoryPageView', histogramValue, HistoryPageViewHistogram.END
     );
   },
 });