MD History: Dynamically update synced tab data

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.
 
 Polymer({
   is: 'synced-device-manager',
 
   properties: {
     // An array of synced devices with synced tab data.
     syncedDevices: {
       type: Array,
       value: []
     }
   },
 
   /**
    * Re-organises the sessionList information.
    */
   addSyncedHistory: function(sessionList) {
-    // Does not add more items onto the page when the sessionList updates.
-    // TODO(yingran) : update the cards dynamically by refreshing the tab list
-    // and last update time for each synced tab card.
+    // Update synced device cards when the user modifies tabs in any synced
+    // device.
     if (this.syncedDevices.length > 0) {
-      return;
-    }
-
-    for (var i = 0; i < sessionList.length && sessionList[i].windows[0]; i++) {
-      this.push('syncedDevices', {
-        device: sessionList[i].name,
-        lastUpdateTime: '- ' + sessionList[i].modifiedTime,
-        tabs: sessionList[i].windows[0].tabs,
-      });
+      var devices =
+          Polymer.dom(this.root).querySelectorAll('synced-device-card');
+      for (var i = 0; i < devices.length; i++) {
+        for (var j = 0; j < sessionList.length &&
+            sessionList[j].windows[0]; j++) {
+          if (devices[i].device == sessionList[j].name) {
+            devices[i].lastUpdateTime = '- ' + sessionList[j].modifiedTime;
+            devices[i].tabs = sessionList[j].windows[0].tabs;
+            sessionList.splice(j, 1);
+          }
+        }
+      }
+    // Sets up the initial synced device cards.
+    } else {
+      for (var i = 0; i < sessionList.length &&
+          sessionList[i].windows[0]; i++) {
+        this.push('syncedDevices', {
+          device: sessionList[i].name,
+          lastUpdateTime: '- ' + sessionList[i].modifiedTime,
+          tabs: sessionList[i].windows[0].tabs,
+        });
+      }
     }
   }
 });