Reland DownloadItem::Observer::OnDownloadDestroyed() replaces DownloadItem::REMOVING

chrome/browser/download/download_status_updater.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_DOWNLOAD_DOWNLOAD_STATUS_UPDATER_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_STATUS_UPDATER_H_
 
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 21 matching lines @@
   // manager when the manager is shutdown.
   void AddManager(content::DownloadManager* manager);
 
   // Methods inherited from content::DownloadManager::Observer.
   virtual void ModelChanged(content::DownloadManager* manager) OVERRIDE;
   virtual void ManagerGoingDown(content::DownloadManager* manager) OVERRIDE;
 
   // Methods inherited from content::DownloadItem::Observer.
   virtual void OnDownloadUpdated(content::DownloadItem* download) OVERRIDE;
   virtual void OnDownloadOpened(content::DownloadItem* download) OVERRIDE;
+  virtual void OnDownloadDestroyed(content::DownloadItem* download) OVERRIDE;
 
  protected:
   // Update the app icon. Virtual to be overridable for testing.
   virtual void UpdateAppIconDownloadProgress();
 
  private:
   // Update the internal state tracking an item.
   void UpdateItem(content::DownloadItem* download);
 
   std::set<content::DownloadManager*> managers_;
   std::set<content::DownloadItem*> items_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadStatusUpdater);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_STATUS_UPDATER_H_