Move the download code to new directories:

chrome/browser/download/download_manager.h

 // Copyright (c) 2006-2008 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.
 //
 // The DownloadManager object manages the process of downloading, including
 // updates to the history system and providing the information for displaying
 // the downloads view in the Destinations tab. There is one DownloadManager per
 // active profile in Chrome.
 //
 // Each download is represented by a DownloadItem, and all DownloadItems
@@ skipping 14 matching lines @@
 // Use AddObserver() / RemoveObserver() on the appropriate download object to
 // receive state updates.
 //
 // Download state persistence:
 // The DownloadManager uses the history service for storing persistent
 // information about the state of all downloads. The history system maintains a
 // separate table for this called 'downloads'. At the point that the
 // DownloadManager is constructed, we query the history service for the state of
 // all persisted downloads.
 
-#ifndef CHROME_BROWSER_DOWNLOAD_MANAGER_H__
-#define CHROME_BROWSER_DOWNLOAD_MANAGER_H__
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_H__
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_H__
 
 #include <string>
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/observer_list.h"
 #include "base/ref_counted.h"
@@ skipping 426 matching lines @@
   PendingFinishedMap pending_finished_downloads_;
 
   // The "Save As" dialog box used to ask the user where a file should be
   // saved.
   scoped_refptr<SelectFileDialog> select_file_dialog_;
 
   DISALLOW_EVIL_CONSTRUCTORS(DownloadManager);
 };
 
 
-#endif  // CHROME_BROWSER_DOWNLOAD_MANAGER_H__
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_H__