Modify the "dangerous download" algorithm as follows. Original patch by Pier...

chrome/common/render_messages_params.h

 // Copyright (c) 2010 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_COMMON_RENDER_MESSAGES_PARAMS_H_
 #define CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 451 matching lines @@
 
   // Indicates which frame (or worker context) the request is being loaded into,
   // or kNoHostId.
   int appcache_host_id;
 
   // Optional upload data (may be null).
   scoped_refptr<net::UploadData> upload_data;
 
   bool download_to_file;
 
+  // True if the request was user initiated.
+  bool has_user_gesture;
+
   // The following two members are specified if the request is initiated by
   // a plugin like Gears.
 
   // Contains the id of the host renderer.
   int host_renderer_id;
 
   // Contains the id of the host render view.
   int host_render_view_id;
 };
 
@@ skipping 849 matching lines @@
 struct ParamTraits<ViewHostMsg_AccessibilityNotification_Params> {
   typedef ViewHostMsg_AccessibilityNotification_Params param_type;
   static void Write(Message* m, const param_type& p);
   static bool Read(const Message* m, void** iter, param_type* p);
   static void Log(const param_type& p, std::string* l);
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_