MD History: Get sign in state from backend when refreshing the page

chrome/browser/resources/md_history/synced_device_manager.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.
 
 /**
  * @typedef {{device: string,
  *           lastUpdateTime: string,
  *           separatorIndexes: !Array<number>,
  *           timestamp: number,
  *           tabs: !Array<!ForeignSessionTab>,
@@ skipping 23 matching lines @@
      * @type {!Array<!ForeignDeviceInternal>}
      */
     syncedDevices_: {
       type: Array,
       value: function() { return []; }
     },
 
     /** @private */
     signInState_: {
       type: Boolean,
-      value: loadTimeData.getBoolean('isUserSignedIn'),
+      value: true,

[calamity, 2016/07/29 05:14:59]

You might want to leave this in... I think this will be janky with non-signed in
profiles if you go directly to chrome://history/syncedTabs.

[lshang, 2016/07/29 06:11:58]

Done.

     },
 
     /** @private */
     guestSession_: {
       type: Boolean,
       value: loadTimeData.getBoolean('isGuestSession'),
     },
 
     /** @private */
     fetchingSyncedTabs_: {
       type: Boolean,
       value: false,
     }
   },
 
+  /** @override */
+  attached: function() {
+    // When user signs in or out with MD History tab open, the internal sign in
+    // state will be updated, but refreshing the page will still get the
+    // outdated state. Get the current state from backend when element is
+    // attached.
+    this.getSignInState_();

[calamity, 2016/07/29 05:14:59]

No need for a method here, just chrome.send('otherDevicesInitialized').

The comment // Update the sign in state. is probably sufficient. The current
comment is a bit too specific.

[lshang, 2016/07/29 06:11:58]

Done.

+  },
+
   /**
    * @param {!ForeignSession} session
    * @return {!ForeignDeviceInternal}
    */
   createInternalDevice_: function(session) {
     var tabs = [];
     var separatorIndexes = [];
     for (var i = 0; i < session.windows.length; i++) {
       var windowId = session.windows[i].sessionId;
       var newTabs = session.windows[i].tabs;
@@ skipping 26 matching lines @@
     return {
       device: session.name,
       lastUpdateTime: '– ' + session.modifiedTime,
       separatorIndexes: separatorIndexes,
       timestamp: session.timestamp,
       tabs: tabs,
       tag: session.tag,
     };
   },
 
+  /** @private */
+  getSignInState_: function() {
+    chrome.send('getSignInState');
+  },
 
   onSignInTap_: function() {
     chrome.send('SyncSetupShowSetupUI');
     chrome.send('SyncSetupStartSignIn', [false]);
   },
 
   /** @private */
   clearDisplayedSyncedDevices_: function() {
     this.syncedDevices_ = [];
   },
@@ skipping 88 matching lines @@
     // User signed in, show the loading message when querying for synced
     // devices.
     this.fetchingSyncedTabs_ = true;
   },
 
   searchTermChanged: function(searchTerm) {
     this.clearDisplayedSyncedDevices_();
     this.updateSyncedDevices(this.sessionList);
   }
 });