[MD History] Hide empty synced device cards.

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,
  *           opened: boolean,
  *           separatorIndexes: !Array<number>,
  *           timestamp: number,
@@ skipping 186 matching lines @@
       md_history.BrowserService.getInstance().recordAction(
           'Signin_Impression_FromRecentTabs');
     }
 
     return show;
   },
 
   /**
    * Decide what message should be displayed when user is logged in and there
    * are no synced tabs.
-   * @param {boolean} fetchingSyncedTabs
    * @return {string}
    */
-  noSyncedTabsMessage: function(fetchingSyncedTabs) {
-    return loadTimeData.getString(
-        fetchingSyncedTabs ? 'loading' : 'noSyncedResults');
+  noSyncedTabsMessage: function() {
+    var stringName = this.fetchingSyncedTabs_ ? 'loading' : 'noSyncedResults';
+    if (this.searchTerm !== '')
+      stringName = 'noSearchResults';
+    return loadTimeData.getString(stringName);
   },
 
   /**
    * Replaces the currently displayed synced tabs with |sessionList|. It is
    * common for only a single session within the list to have changed, We try to
    * avoid doing extra work in this case. The logic could be more intelligent
    * about updating individual tabs rather than replacing whole sessions, but
    * this approach seems to have acceptable performance.
    * @param {?Array<!ForeignSession>} sessionList
    */
   updateSyncedDevices: function(sessionList) {
     this.fetchingSyncedTabs_ = false;
 
     if (!sessionList)
       return;
 
     if (sessionList.length > 0 && !this.hasSeenForeignData_) {
       this.hasSeenForeignData_ = true;
       md_history.BrowserService.getInstance().recordHistogram(
         SYNCED_TABS_HISTOGRAM_NAME, SyncedTabsHistogram.HAS_FOREIGN_DATA,
         SyncedTabsHistogram.LIMIT);
     }
 
     // First, update any existing devices that have changed.
     var updateCount = Math.min(sessionList.length, this.syncedDevices_.length);
     for (var i = 0; i < updateCount; i++) {
       var oldDevice = this.syncedDevices_[i];
       if (oldDevice.tag != sessionList[i].tag ||
           oldDevice.timestamp != sessionList[i].timestamp) {
-        this.splice(
-            'syncedDevices_', i, 1, this.createInternalDevice_(sessionList[i]));
+        device = this.createInternalDevice_(sessionList[i]);

[tsergeant, 2016/09/22 06:58:50]

Nit: Add `var`

[calamity, 2016/09/22 07:52:53]

Done.

+        if (device.tabs.length != 0)
+          this.splice('syncedDevices_', i, 1, device);
       }
     }
 
     if (sessionList.length >= this.syncedDevices_.length) {
       // The list grew; append new items.
       for (var i = updateCount; i < sessionList.length; i++) {
-        this.push('syncedDevices_', this.createInternalDevice_(sessionList[i]));
+        device = this.createInternalDevice_(sessionList[i]);

[tsergeant, 2016/09/22 06:58:50]

Nit: Here too

(or declare `var device;` at the top of the method. Whichever you prefer)

[calamity, 2016/09/22 07:52:53]

Done.

+        if (device.tabs.length != 0)
+          this.push('syncedDevices_', device);
       }
     } else {
       // The list shrank; remove deleted items.
       this.splice(
           'syncedDevices_', updateCount,
           this.syncedDevices_.length - updateCount);
     }
   },
 
   /**
@@ skipping 20 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);
   }
 });