Allow data URLs to trigger downloads, as they do in Firefox....

net/base/data_url.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.
 
 #ifndef NET_BASE_DATA_URL_H_
 #define NET_BASE_DATA_URL_H_
 #pragma once
 
 #include <string>
 
@@ skipping 19 matching lines @@
  public:
   // This method can be used to parse a 'data' URL into its component pieces.
   //
   // The resulting mime_type is normalized to lowercase.  The data is the
   // decoded data (e.g.., if the data URL specifies base64 encoding, then the
   // returned data is base64 decoded, and any %-escaped bytes are unescaped).
   //
   // If the URL is malformed, then this method will return false, and its
   // output variables will remain unchanged.  On success, true is returned.
   //
+  // OPTIONAL: If |data| is NULL, then the <data> section will not be parsed
+  //           or validated.
+  //
   static bool Parse(const GURL& url,
                     std::string* mime_type,
                     std::string* charset,
                     std::string* data);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_DATA_URL_H_