Reapply and fix r73019. BalloonViewImpl has a different implemementation on

chrome/browser/notifications/balloon_collection.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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_H_
 #define CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_H_
 #pragma once
 
 #include <deque>
@@ skipping 29 matching lines @@
     LOWER_RIGHT        = 1,
     UPPER_LEFT         = 2,
     LOWER_LEFT         = 3,
 
     // The default position is different on different platforms.
     DEFAULT_POSITION   = -1
   };
 
   static BalloonCollection* Create();
 
-  BalloonCollection()
-      : space_change_listener_(NULL) {
-  }
+  BalloonCollection();
 
-  virtual ~BalloonCollection() {}
+  virtual ~BalloonCollection();
 
   // Adds a new balloon for the specified notification.
   virtual void Add(const Notification& notification,
                    Profile* profile) = 0;
 
   // Removes any balloons that have this notification id.  Returns
   // true if anything was removed.
   virtual bool RemoveById(const std::string& id) = 0;
 
   // Removes any balloons that have this source origin.  Returns
@@ skipping 36 matching lines @@
  protected:
   // Non-owned pointer to an object listening for space changes.
   BalloonSpaceChangeListener* space_change_listener_;
 
   // For use only with testing. This callback is invoked when a balloon
   // is added or removed from the collection.
   scoped_ptr<Callback0::Type> on_collection_changed_callback_;
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_H_