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

chrome/browser/download/download_completion_observer_win.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_COMPLETION_OBSERVER_WIN_H_
-#define CHROME_BROWSER_DOWNLOAD_COMPLETION_OBSERVER_WIN_H_
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_OBSERVER_WIN_H_
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_OBSERVER_WIN_H_
 
 #include <set>
 
 #include "base/basictypes.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 
 // Tracks download item completions and notifies any interested parties
 // (Windows 8 metro) about the same. On Windows 8 we display metro style
 // notifications when a download completes.
 class DownloadCompletionObserver
     : public content::DownloadManager::Observer,
       public content::DownloadItem::Observer {
  public:
   explicit DownloadCompletionObserver(content::DownloadManager* manager);
   ~DownloadCompletionObserver();
 
   // Methods inherited from content::DownloadManager::Observer.
   virtual void OnDownloadCreated(
       content::DownloadManager* manager, content::DownloadItem* download)
       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;
 
  private:
   void ClearDownloadItems();
 
   std::set<content::DownloadItem*> download_items_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadCompletionObserver);
 };
 
-#endif  // CHROME_BROWSER_DOWNLOAD_COMPLETION_OBSERVER_WIN_H_
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_OBSERVER_WIN_H_