Sync online wallpaper

chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js

 // Copyright (c) 2013 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.
 
 var WALLPAPER_PICKER_WIDTH = 574;
 var WALLPAPER_PICKER_HEIGHT = 420;
 
 var wallpaperPickerWindow;
 
 var surpriseWallpaper = null;
@@ skipping 18 matching lines @@
  */
 SurpriseWallpaper.prototype.tryChangeWallpaper = function() {
   var self = this;
   var onFailure = function() {
     self.retryLater_();
     self.fallbackToLocalRss_();
   };
   // Try to fetch newest rss as document from server first. If any error occurs,
   // proceed with local copy of rss.
   WallpaperUtil.fetchURL(Constants.WallpaperRssURL, 'document', function(xhr) {
-    WallpaperUtil.saveToLocalStorage(Constants.AccessRssKey,
-        new XMLSerializer().serializeToString(xhr.responseXML));
+    WallpaperUtil.saveToStorage(Constants.AccessRssKey,
+        new XMLSerializer().serializeToString(xhr.responseXML), false);
     self.updateSurpriseWallpaper(xhr.responseXML);
   }, onFailure);
 };
 
 /**
  * Retries changing the wallpaper 1 hour later. This is called when fetching the
  * rss or wallpaper from server fails.
  * @private
  */
 SurpriseWallpaper.prototype.retryLater_ = function() {
@@ skipping 81 matching lines @@
 SurpriseWallpaper.prototype.setRandomWallpaper_ = function(dateString) {
   var self = this;
   Constants.WallpaperLocalStorage.get(Constants.AccessManifestKey,
                                       function(items) {
     var manifest = items[Constants.AccessManifestKey];
     if (manifest) {
       var index = Math.floor(Math.random() * manifest.wallpaper_list.length);
       var wallpaper = manifest.wallpaper_list[index];
       var wallpaperURL = wallpaper.base_url + Constants.HighResolutionSuffix;
       var onSuccess = function() {
-        WallpaperUtil.saveToLocalStorage(
-            Constants.AccessLastSurpriseWallpaperChangedDate, dateString);
+        WallpaperUtil.saveToStorage(
+            Constants.AccessLastSurpriseWallpaperChangedDate,
+            dateString,
+            false);
       }
       WallpaperUtil.setOnlineWallpaper(wallpaperURL, wallpaper.default_layout,
           onSuccess, self.retryLater_.bind(self));
     }
   });
 };
 
 /**
  * Sets wallpaper to the wallpaper specified by item from rss. If downloading
  * the wallpaper fails, retry one hour later.
@@ skipping 19 matching lines @@
     }
   }, onFailure);
 };
 
 /**
  * Disables the wallpaper surprise me feature. Clear all alarms and states.
  */
 SurpriseWallpaper.prototype.disable = function() {
   chrome.alarms.clearAll();
   // Makes last changed date invalid.
-  WallpaperUtil.saveToLocalStorage(
-      Constants.AccessLastSurpriseWallpaperChangedDate, '');
+  WallpaperUtil.saveToStorage(Constants.AccessLastSurpriseWallpaperChangedDate,
+                              '', false);
 };
 
 /**
  * Changes current wallpaper and sets up an alarm to schedule next change around
  * midnight.
  */
 SurpriseWallpaper.prototype.next = function() {
   var nextUpdate = this.nextUpdateTime(new Date());
   chrome.alarms.create({when: nextUpdate});
   this.tryChangeWallpaper();
@@ skipping 34 matching lines @@
   });
 });
 
 chrome.storage.onChanged.addListener(function(changes, namespace) {
   if (changes[Constants.AccessSurpriseMeEnabledKey]) {
     if (changes[Constants.AccessSurpriseMeEnabledKey].newValue) {
       SurpriseWallpaper.getInstance().next();
     } else {
       SurpriseWallpaper.getInstance().disable();
     }
+  } else if (changes[Constants.AccessWallpaperInfoKey]) {

[flackr, 2013/04/26 03:51:16]

This shouldn't be else if, just if. Both keys may have changed.

[bshe, 2013/04/26 16:56:51]

Done.

+    var newValue = changes[Constants.AccessWallpaperInfoKey].newValue;
+    var oldValue = changes[Constants.AccessWallpaperInfoKey].oldValue;
+    // oldValue equals undefined indicate that sync just happened.
+    if (oldValue == undefined &&

[flackr, 2013/04/26 03:51:16]

Why only if oldValue is undefined? I think it would be nice to have a change on
one computer change the wallpapers on the other computers.

[bshe, 2013/04/26 16:56:51]

You are right. It doesn't handle the case you mention.

I wasn't able to find a easy way to detect if the value is changed because of
sync or user action. But after spend more time on it, it seems we can use an
extra local value to easily distinguish the two cases.

On 2013/04/26 03:51:16, flackr wrote:

+        newValue.source == Constants.WallpaperSourceEnum.Online) {
+      // TODO(bshe): Consider schedule an alarm to set online wallpaper later
+      // when failed. Note that we need to cancel the retry if user set another
+      // wallpaper before retry alarm invoked.
+      WallpaperUtil.setOnlineWallpaper(newValue.url, newValue.layout,
+          function() {}, function() {});
+    }
   }
 });
 
 chrome.alarms.onAlarm.addListener(function() {
   SurpriseWallpaper.getInstance().next();
 });