Allow partial update for notification update API

chrome/browser/notifications/balloon_collection_base.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.
 
 // Handles the visible notification (or balloons).
 
 #ifndef CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_BASE_H_
 #define CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_BASE_H_
 
 #include <deque>
@@ skipping 16 matching lines @@
   typedef std::deque<Balloon*> Balloons;
 
   // Adds a balloon to the collection. Takes ownership of pointer.
   virtual void Add(Balloon* balloon, bool add_to_front);
 
   // Removes a balloon from the collection (if present).  Frees
   // the pointer after removal.
   virtual void Remove(Balloon* balloon);
 
   // Returns true if any balloon matches the given notification id.
-  virtual bool DoesIdExist(const std::string& id);
+  virtual const Notification* FindById(const std::string& id) const;
 
   // Finds any balloon matching the given notification id, and
   // calls CloseByScript on it.  Returns true if anything was
   // found.
   virtual bool CloseById(const std::string& id);
 
   // Finds all balloons matching the given notification source,
   // and calls CloseByScript on them.  Returns true if anything
   // was found.
   virtual bool CloseAllBySourceOrigin(const GURL& source_origin);
@@ skipping 19 matching lines @@
   int count() const { return static_cast<int>(balloons_.size()); }
 
  private:
   // Queue of active balloons.  Pointers are owned by this class.
   Balloons balloons_;
 
   DISALLOW_COPY_AND_ASSIGN(BalloonCollectionBase);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_BASE_H_