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

chrome/browser/history/download_create_info.h

 // Copyright (c) 2006-2008 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.
 //
 // Download creation struct used for querying the history service.
 
 #ifndef CHROME_BROWSER_HISTORY_DOWNLOAD_CREATE_INFO_H_
 #define CHROME_BROWSER_HISTORY_DOWNLOAD_CREATE_INFO_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/time.h"
 #include "chrome/browser/download/download_file.h"
 #include "googleurl/src/gurl.h"
 
 // Used for informing the download database of a new download, where we don't
 // want to pass DownloadItems between threads. The history service also uses a
 // vector of these structs for passing us the state of all downloads at
 // initialization time (see DownloadQueryInfo below).
 struct DownloadCreateInfo {
   DownloadCreateInfo(const FilePath& path,
                      const GURL& url,
                      base::Time start_time,
                      int64 received_bytes,
                      int64 total_bytes,
                      int32 state,
-                     int32 download_id);
+                     int32 download_id,
+                     bool has_user_gesture);
   DownloadCreateInfo();
   ~DownloadCreateInfo();
 
   std::string DebugString() const;
 
   // DownloadItem fields
   FilePath path;
   GURL url;
   GURL referrer_url;
   FilePath suggested_path;
   // A number that should be added to the suggested path to make it unique.
   // 0 means no number should be appended.  Not actually stored in the db.
   int path_uniquifier;
   base::Time start_time;
   int64 received_bytes;
   int64 total_bytes;
   int32 state;
   int32 download_id;
+  bool has_user_gesture;
   int child_id;
   int render_view_id;
   int request_id;
   int64 db_handle;
   std::string content_disposition;
   std::string mime_type;
   // The value of the content type header sent with the downloaded item.  It
   // may be different from |mime_type|, which may be set based on heuristics
   // which may look at the file extension and first few bytes of the file.
   std::string original_mime_type;
@@ skipping 10 matching lines @@
   // Whether this download is for extension install or not.
   bool is_extension_install;
   // The charset of the referring page where the download request comes from.
   // It's used to construct a suggested filename.
   std::string referrer_charset;
   // The download file save info.
   DownloadSaveInfo save_info;
 };
 
 #endif  // CHROME_BROWSER_HISTORY_DOWNLOAD_CREATE_INFO_H_