[Downloads] Always call DM::StartDownload() for explicit downloads.

content/browser/download/download_file_impl.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_FILE_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_
 
 #include "content/browser/download/download_file.h"
 
 #include "base/memory/ref_counted.h"
@@ skipping 18 matching lines @@
  public:
   // Takes ownership of the object pointed to by |request_handle|.
   // |bound_net_log| will be used for logging the download file's events.
   // May be constructed on any thread.  All methods besides the constructor
   // (including destruction) must occur on the FILE thread.
   //
   // Note that the DownloadFileImpl automatically reads from the passed in
   // stream, and sends updates and status of those reads to the
   // DownloadDestinationObserver.
   DownloadFileImpl(
-    scoped_ptr<DownloadSaveInfo> save_info,
+    const DownloadSaveInfo& save_info,
     const base::FilePath& default_downloads_directory,
     const GURL& url,
     const GURL& referrer_url,
     bool calculate_hash,
-    scoped_ptr<ByteStreamReader> stream,
+    scoped_ptr<net::FileStream> file_stream,
+    scoped_ptr<ByteStreamReader> byte_stream,
     const net::BoundNetLog& bound_net_log,
     scoped_ptr<PowerSaveBlocker> power_save_blocker,
     base::WeakPtr<DownloadDestinationObserver> observer);
 
   virtual ~DownloadFileImpl();
 
   // DownloadFile functions.
   virtual void Initialize(const InitializeCallback& callback) OVERRIDE;
   virtual void RenameAndUniquify(
       const base::FilePath& full_path,
@@ skipping 52 matching lines @@
 
   // RAII handle to keep the system from sleeping while we're downloading.
   scoped_ptr<PowerSaveBlocker> power_save_blocker_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_