Added DownloadProcessHandle 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_