Add a Create method to DesktopNotificationHandler and stubs for the notification objects.

chrome/browser/notifications/notification_ui_manager.h

Index: chrome/browser/notifications/notification_ui_manager.h
diff --git a/chrome/browser/notifications/notification_ui_manager.h b/chrome/browser/notifications/notification_ui_manager.h
index fb78473e436d536a7f0480e797064cf91ac7c62d..2c6d931d5e51b4a51bf660f2afeb8f627d0fba9e 100644
--- a/chrome/browser/notifications/notification_ui_manager.h
+++ b/chrome/browser/notifications/notification_ui_manager.h
@@ -30,7 +30,6 @@ class NotificationUIManager
     : public BalloonCollection::BalloonSpaceChangeListener,
       public NotificationObserver {
  public:
-  explicit NotificationUIManager(PrefService* local_state);
   virtual ~NotificationUIManager();
 
   // Creates an initialized UI manager with a new balloon collection
@@ -38,6 +37,12 @@ class NotificationUIManager
   // Except for unit tests, this is the way to construct the object.
   static NotificationUIManager* Create(PrefService* local_state);
 
+  // Creates an initialized UI manager with the given balloon collection
+  // and the listener relationship setup.
+  // Used primarily by unit tests.
+  static NotificationUIManager* Create(PrefService* local_state,
+                                       BalloonCollection* balloons);
+
   // Registers preferences.
   static void RegisterPrefs(PrefService* prefs);
 
@@ -75,6 +80,8 @@ class NotificationUIManager
   void SetPositionPreference(BalloonCollection::PositionPreference preference);
 
  private:
+  explicit NotificationUIManager(PrefService* local_state);
+
   // NotificationObserver override.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,