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

chrome/browser/resources/md_history/history.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.
 
 // Send the history query immediately. This allows the query to process during
 // the initial page startup.
 chrome.send('queryHistory', ['', 0, 0, 0, RESULTS_PER_PAGE]);
 chrome.send('getForeignSessions');
 
 /** @type {Promise} */
@@ skipping 50 matching lines @@
   waitForAppUpgrade().then(function() {
     var app = /** @type {HistoryAppElement} */ ($('history-app'));
     app.showSidebarFooter = includeOtherFormsOfBrowsingHistory;
     app.hasSyncedResults = hasSyncedResults;
   });
 }
 
 /**
  * Receives the synced history data. An empty list means that either there are
  * no foreign sessions, or tab sync is disabled for this profile.
- * |isTabSyncEnabled| makes it possible to distinguish between the cases.
  *
  * @param {!Array<!ForeignSession>} sessionList Array of objects describing the
  *     sessions from other devices.
- * @param {boolean} isTabSyncEnabled Is tab sync enabled for this profile?
  */
-function setForeignSessions(sessionList, isTabSyncEnabled) {
+function setForeignSessions(sessionList) {
   waitForAppUpgrade().then(function() {
     /** @type {HistoryAppElement} */($('history-app'))
-        .setForeignSessions(sessionList, isTabSyncEnabled);
+        .setForeignSessions(sessionList);
   });
 }
 
 /**
  * Called when the history is deleted by someone else.
  */
 function historyDeleted() {
   waitForAppUpgrade().then(function() {
     /** @type {HistoryAppElement} */($('history-app'))
         .historyDeleted();
   });
 }
 
 /**
  * Called by the history backend after user's sign in state changes.
  * @param {boolean} isUserSignedIn Whether user is signed in or not now.
  */
 function updateSignInState(isUserSignedIn) {
   waitForAppUpgrade().then(function() {
     if ($('history-app')) {
       /** @type {HistoryAppElement} */($('history-app'))
           .updateSignInState(isUserSignedIn);
     }
   });
 }