Change DownloadProcessHandle to be more of an encapsulated class.

chrome/browser/download/download_process_handle.h

-// Copyright (c) 2011 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_PROCESS_HANDLE_H_
-#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_PROCESS_HANDLE_H_
-#pragma once
-
-class DownloadManager;
-class ResourceDispatcherHost;
-class TabContents;
-
-// A handle used by the download system for operations on external
-// objects associated with the download (e.g. URLRequest, TabContents,
-// DownloadManager).
-// This class needs to be copyable, so we can pass it across threads and not
-// worry about lifetime or const-ness.
-class DownloadProcessHandle {
- public:
-  DownloadProcessHandle();
-  DownloadProcessHandle(int child_id, int render_view_id, int request_id);
-
-  // These functions must be called on the UI thread.
-  TabContents* GetTabContents();
-  DownloadManager* GetDownloadManager();
-
-  int child_id() const { return child_id_; }
-  int render_view_id() const { return render_view_id_; }
-  int request_id() const { return request_id_; }
-
- private:
-  // The ID of the child process that started the download.
-  int child_id_;
-
-  // The ID of the render view that started the download.
-  int render_view_id_;
-
-  // The ID associated with the request used for the download.
-  int request_id_;
-};
-
-#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_PROCESS_HANDLE_H_