net: Add namespace net to the remaining files under url_request directory.

chrome/browser/plugin_download_helper.h

Index: chrome/browser/plugin_download_helper.h
diff --git a/chrome/browser/plugin_download_helper.h b/chrome/browser/plugin_download_helper.h
index cccf3f0a27ee444f2e00024e7b82a9e48532c4c3..63b24bea3de366916728d891b8cfe0c8acb1e592 100644
--- a/chrome/browser/plugin_download_helper.h
+++ b/chrome/browser/plugin_download_helper.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -36,7 +36,7 @@ class PluginDownloadUrlHelper : public net::URLRequest::Delegate {
                           PluginDownloadUrlHelper::DownloadDelegate* delegate);
   ~PluginDownloadUrlHelper();
 
-  void InitiateDownload(URLRequestContext* request_context);
+  void InitiateDownload(net::URLRequestContext* request_context);
 
   // net::URLRequest::Delegate
   virtual void OnAuthRequired(net::URLRequest* request,