Fix the issue that wallpaper changes twice when both "onChanged" and "onAlarm" are fired.

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

Index: chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js
diff --git a/chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js b/chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js
index 9e693e4c5843be3f6589941d6df2b8dcbe520418..a6f44c5bc3ef2e963f6dd3af688bd788e8cbaecb 100644
--- a/chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js
+++ b/chrome/browser/resources/chromeos/wallpaper_manager/js/event_page.js
@@ -115,11 +115,8 @@ SurpriseWallpaper.prototype.updateRandomWallpaper_ = function() {
   var self = this;
   Constants.WallpaperSyncStorage.get(
       Constants.AccessLastSurpriseWallpaperChangedDate, function(items) {
-    var dateString = new Date().toDateString();
-    // At most one random wallpaper per day.
-    if (items[Constants.AccessLastSurpriseWallpaperChangedDate] != dateString) {
-      self.setRandomWallpaper_(dateString);
-    }
+    var today = new Date().toDateString();
+    self.setRandomWallpaper_(today);
   });
 };
 
@@ -150,6 +147,8 @@ SurpriseWallpaper.prototype.setRandomWallpaper_ = function(dateString) {
             Constants.AccessLastSurpriseWallpaperChangedDate,
             dateString,
             true);
+        WallpaperUtil.saveWallpaperInfo(wallpaperURL, wallpaper.default_layout,
+          Constants.WallpaperSourceEnum.Online);

[bshe, 2015/03/04 19:45:39]

nit: 4 spaces indention for new line.

[xdai1, 2015/03/04 21:32:39]

Done.

       };
       WallpaperUtil.setOnlineWallpaper(wallpaperURL, wallpaper.default_layout,
           onSuccess, self.retryLater_.bind(self));
@@ -194,13 +193,22 @@ SurpriseWallpaper.prototype.disable = function() {
 };
 
 /**
- * Changes current wallpaper and sets up an alarm to schedule next change around
- * midnight.
+ * Changes current wallpaper once a day and sets up an alarm to schedule next
+ * change around midnight. If the surprise wallpaper was already set toady,
+ * then don't change it any more.
  */
 SurpriseWallpaper.prototype.next = function() {
   var nextUpdate = this.nextUpdateTime(new Date());
   chrome.alarms.create({when: nextUpdate});
-  this.tryChangeWallpaper();
+
+  var self = this;
+  Constants.WallpaperSyncStorage.get(

[bshe, 2015/03/04 19:45:39]

why do you want to move the check to here? Looks like we skipped checking from
wallpaper from rss this way, I worry it might cause problem.

[xdai1, 2015/03/04 21:32:39]

Since when surprise me is enabled, we only change wallpaper once a day (no
matter it's rss special wallpaper or a random surprise wallpaper). So it won't
miss rss wallpaper here. Both way will do the same thing. But I think it might
be more clear to put the check here?

[bshe, 2015/03/05 14:53:19]

Rss wallpaper is not saved to sync storage and we prefer to use the rss
wallpaper over random online wallpaper. Set rss wallpaper might not be success
on Chromebook on first try. We dont want to block the second try (1 hour later,
see retryLater_ function) in this case. If there is no bug that you are trying
to fix with this move, I would prefer to keep the check in the old place.

+    Constants.AccessLastSurpriseWallpaperChangedDate, function(items) {
+      var today = new Date().toDateString();
+      if (items[Constants.AccessLastSurpriseWallpaperChangedDate] != today) {
+        self.tryChangeWallpaper();
+    }
+  });
 };
 
 /**
@@ -277,33 +285,57 @@ chrome.storage.onChanged.addListener(function(changes, namespace) {
     }
 
     if (changes[Constants.AccessSyncWallpaperInfoKey]) {
-      var newValue = changes[Constants.AccessSyncWallpaperInfoKey].newValue;
-      Constants.WallpaperLocalStorage.get(Constants.AccessLocalWallpaperInfoKey,
-                                          function(items) {
-        // Normally, the wallpaper info saved in local storage and sync storage
-        // are the same. If the synced value changed by sync service, they may
-        // different. In that case, change wallpaper to the one saved in sync
-        // storage and update the local value.
-        var localValue = items[Constants.AccessLocalWallpaperInfoKey];
-        if (localValue == undefined ||
-            localValue.url != newValue.url ||
-            localValue.layout != newValue.layout ||
-            localValue.source != newValue.source) {
-          if (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() {});
-          } else if (newValue.source == Constants.WallpaperSourceEnum.Custom) {
-            WallpaperUtil.setCustomWallpaperFromSyncFS(newValue.url,
-                                                       newValue.layout);
-          } else if (newValue.source == Constants.WallpaperSourceEnum.Default) {
-            chrome.wallpaperPrivate.resetWallpaper();
+      var syncInfo = changes[Constants.AccessSyncWallpaperInfoKey].newValue;
+
+      Constants.WallpaperSyncStorage.get(Constants.AccessSurpriseMeEnabledKey,
+                                         function(enabledItems) {
+        var syncSurpriseMeEnabled =
+          enabledItems[Constants.AccessSurpriseMeEnabledKey];

[bshe, 2015/03/04 19:45:39]

nit: 4 spaces indention

[xdai1, 2015/03/04 21:32:39]

Done.

+
+        Constants.WallpaperSyncStorage.get(
+          Constants.AccessLastSurpriseWallpaperChangedDate, function(items) {

[bshe, 2015/03/04 19:45:39]

ditto

[xdai1, 2015/03/04 21:32:39]

Done.

+          var syncLastSurpriseMeChangedDate =

[bshe, 2015/03/04 19:45:39]

nit: function implementation should have 2 space indention.

[xdai1, 2015/03/04 21:32:39]

I think it already has 2 space indention?

+              items[Constants.AccessLastSurpriseWallpaperChangedDate];
+
+          var today = new Date().toDateString();
+          // If SurpriseMe is enabled and surprise wallpaper hasn't been changed
+          // today, we should not sync the change, instead onAlarm() will be
+          // triggered to update a surprise me wallpaper.
+          if (!syncSurpriseMeEnabled || (syncSurpriseMeEnabled &&
+                                syncLastSurpriseMeChangedDate == today)) {

[bshe, 2015/03/04 19:45:39]

nit: indention is off. Consider this:
if (!syncSurpriseMeEnabled ||
    (syncSurpriseMeEnabled && syncLastSurpriseMeChangedDate == today)) {
....
}

[xdai1, 2015/03/04 21:32:39]

Done.

+            Constants.WallpaperLocalStorage.get(
+              Constants.AccessLocalWallpaperInfoKey, function(infoItems) {
+                var localInfo =
+                  infoItems[Constants.AccessLocalWallpaperInfoKey];

[bshe, 2015/03/04 19:45:39]

nit: 4 space indention

[xdai1, 2015/03/04 21:32:39]

Done.

+                // Normally, the wallpaper info saved in local storage and sync
+                // storage are the same. If the synced value changed by sync
+                // service, they may different. In that case, change wallpaper
+                // to the one saved in sync storage and update the local value.
+                if (localInfo == undefined ||
+                    localInfo.url != syncInfo.url ||
+                    localInfo.layout != syncInfo.layout ||
+                    localInfo.source != syncInfo.source) {
+                  if (syncInfo.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(syncInfo.url,
+                        syncInfo.layout, function() {}, function() {});
+                  } else if (syncInfo.source ==
+                    Constants.WallpaperSourceEnum.Custom) {
+                      WallpaperUtil.setCustomWallpaperFromSyncFS(syncInfo.url,
+                          syncInfo.layout);
+                  } else if (syncInfo.source ==
+                              Constants.WallpaperSourceEnum.Default) {
+                      chrome.wallpaperPrivate.resetWallpaper();
+                  }
+                  WallpaperUtil.saveToStorage(
+                        Constants.AccessLocalWallpaperInfoKey, syncInfo, false);
+                }
+            });
           }
-          WallpaperUtil.saveToStorage(Constants.AccessLocalWallpaperInfoKey,
-                                      newValue, false);
-        }
+        });
       });
     }
   });