MD History: Display synced tabs history.

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.
 
 // Globals:
 /** @const */ var RESULTS_PER_PAGE = 150;
 
 /**
  * Amount of time between pageviews that we consider a 'break' in browsing,
  * measured in milliseconds.
  * @const
  */
 var BROWSING_GAP_TIME = 15 * 60 * 1000;
 
-window.addEventListener('load', function() {
-  chrome.send('queryHistory', ['', 0, 0, 0, RESULTS_PER_PAGE]);
-});
-
 /**
  * Listens for history-item being selected or deselected (through checkbox)
  * and changes the view of the top toolbar.
  */
 window.addEventListener('history-checkbox-select', function(e) {
   $('toolbar').count += e.detail.countAddition;
 });
 
 /**
  * Listens for call to cancel selection and loops through all items to set
@@ skipping 31 matching lines @@
   }
 });
 
 /**
  * Resizing browser window will cause the overflow menu to close.
  */
 window.addEventListener('resize', function() {
   $('history-list').closeMenu();
 });
 
+/**
+ * Switches between displaying history data and synced tabs data for the page.
+ */
+window.addEventListener('switch-display', function(e) {
+  $('synced-device-manager').hidden = e.detail.display != 'synced-tabs-button';

[tsergeant, 2016/03/01 03:58:22]

Did you experiment with using something other than 'hidden' to improve
performance?

[calamity, 2016/03/08 02:46:51]

I looked into it. It didn't work out so well. This will do for now, I'd rather
fix this in a follow-up patch, especially if we have to do weird things to make
it work well.

+  $('history-list').hidden = e.detail.display != 'history-button';
+});
+
+window.addEventListener('load', function() {
+  chrome.send('queryHistory', ['', 0, 0, 0, RESULTS_PER_PAGE]);
+  chrome.send('getForeignSessions');
+});
+
 // Chrome Callbacks-------------------------------------------------------------
 
 /**
  * Our history system calls this function with results from searches.
  * @param {HistoryQuery} info An object containing information about the query.
  * @param {Array<HistoryEntry>} results A list of results.
  */
 function historyResult(info, results) {
   $('history-list').addNewResults(results);
   if (info.finished)
     $('history-list').disableResultLoading();
 }
 
 /**
+ * Receives the synced history data. An empty list means that either there are
+ * no foreign sessions, or tab sync is disabled for this profile.

[tsergeant, 2016/03/01 03:58:22]

This means that it's possible to have no foreign sessions, but the sidebar will
still be enabled? Will this make it possible to switch to a totally empty page?

That's probably okay, but we should make sure we add a message in when there are
no synced tabs (follow-up is fine).

[calamity, 2016/03/08 02:46:51]

Good point™.

+ * |isTabSyncEnabled| makes it possible to distinguish between the cases.
+ *
+ * @param {Array<Session>} sessionList Array of objects describing the sessions
+ *     from other devices.
+ * @param {boolean} isTabSyncEnabled Is tab sync enabled for this profile?
+ */
+function setForeignSessions(sessionList, isTabSyncEnabled) {
+  $('side-bar').hidden = !isTabSyncEnabled;
+  if (isTabSyncEnabled) {

[tsergeant, 2016/03/01 03:58:22]

Nit: {}

[calamity, 2016/03/08 02:46:51]

Done.

+    $('synced-device-manager').addSyncedHistory(sessionList);
+  }
+}
+
+/**
  * Called by the history backend when deletion was succesful.
  */
 function deleteComplete() {
   $('history-list').removeDeletedHistory($('toolbar').count);
   $('toolbar').count = 0;
 }
 
 /**
  * Called by the history backend when the deletion failed.
  */
 function deleteFailed() {
 }
 
 /**
  * Called when the history is deleted by someone else.
  */
 function historyDeleted() {
 }