Allow partial update for notification update API

chrome/browser/notifications/notification_ui_manager.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 11 matching lines @@
  public:
   virtual ~NotificationUIManager() {}
 
   // Creates an initialized UI manager.
   static NotificationUIManager* Create(PrefService* local_state);
 
   // Adds a notification to be displayed. Virtual for unit test override.
   virtual void Add(const Notification& notification,
                    Profile* profile) = 0;
 
-  // Returns true if any notifications match the supplied ID, either currently
-  // displayed or in the queue.
-  virtual bool DoesIdExist(const std::string& notification_id) = 0;
+  // Returns the pointer to a notification if it match the supplied ID, either
+  // currently displayed or in the queue.
+  virtual const Notification* FindById(
+      const std::string& notification_id) const = 0;
 
   // Removes any notifications matching the supplied ID, either currently
   // displayed or in the queue.  Returns true if anything was removed.
   virtual bool CancelById(const std::string& notification_id) = 0;
 
   // Adds the notification_id for each outstanding notification to the set
   // |notification_ids| (must not be NULL).
   virtual std::set<std::string> GetAllIdsByProfileAndSourceOrigin(
       Profile* profile,
       const GURL& source) = 0;
@@ skipping 17 matching lines @@
   static bool DelegatesToMessageCenter();
 
  protected:
   NotificationUIManager() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NotificationUIManager);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_H_