Make the UI an observer of downloads.

content/browser/download/download_item_impl_delegate.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 CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "content/common/content_export.h"
@@ skipping 69 matching lines @@
   // Opens the file associated with this download.
   virtual void OpenDownload(DownloadItemImpl* download);
 
   // Shows the download via the OS shell.
   virtual void ShowDownloadInShell(DownloadItemImpl* download);
 
   // Handle any delegate portions of a state change operation on the
   // DownloadItem.
   virtual void DownloadRemoved(DownloadItemImpl* download);
 
-  // Show the download in the browser.
-  virtual void ShowDownloadInBrowser(DownloadItemImpl* download);
-
   // Assert consistent state for delgate object at various transitions.
   virtual void AssertStateConsistent(DownloadItemImpl* download) const;
 
  private:
   // For "Outlives attached DownloadItemImpl" invariant assertion.
   int count_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemImplDelegate);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_DELEGATE_H_