We should be de-serializing an int64 for the UploadData identifier....

chrome/common/common_param_traits.h

 // Copyright (c) 2009 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.
 
 // This file is used to define IPC::ParamTraits<> specializations for a number
 // of types so that they can be serialized over IPC.  IPC::ParamTraits<>
 // specializations for basic types (like int and std::string) and types in the
 // 'base' project can be found in ipc/ipc_message_utils.h.  This file contains
 // specializations for types that are shared by more than one child process.
 
@@ skipping 264 matching lines @@
   }
   static bool Read(const Message* m, void** iter, param_type* r) {
     bool has_object;
     if (!ReadParam(m, iter, &has_object))
       return false;
     if (!has_object)
       return true;
     std::vector<net::UploadData::Element> elements;
     if (!ReadParam(m, iter, &elements))
       return false;
-    int identifier;
+    int64 identifier;
     if (!ReadParam(m, iter, &identifier))
       return false;
     *r = new net::UploadData;
     (*r)->swap_elements(&elements);
     (*r)->set_identifier(identifier);
     return true;
   }
   static void Log(const param_type& p, std::wstring* l) {
     l->append(L"<net::UploadData>");
   }
@@ skipping 26 matching lines @@
   }
   static void Log(const param_type& p, std::wstring* l) {
     l->append(StringPrintf(L"(%f, %d, %d)",
                            p.boring_score, p.good_clipping, p.at_top));
   }
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_COMMON_PARAM_TRAITS_H_