Support sending a sliced file in chromium....

chrome/common/common_param_traits.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.
 
 // 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 300 matching lines @@
 struct ParamTraits<net::UploadData::Element> {
   typedef net::UploadData::Element param_type;
   static void Write(Message* m, const param_type& p) {
     WriteParam(m, static_cast<int>(p.type()));
     if (p.type() == net::UploadData::TYPE_BYTES) {
       m->WriteData(&p.bytes()[0], static_cast<int>(p.bytes().size()));
     } else {
       WriteParam(m, p.file_path());
       WriteParam(m, p.file_range_offset());
       WriteParam(m, p.file_range_length());
+      WriteParam(m, p.expected_file_modification_time());
     }
   }
   static bool Read(const Message* m, void** iter, param_type* r) {
     int type;
     if (!ReadParam(m, iter, &type))
       return false;
     if (type == net::UploadData::TYPE_BYTES) {
       const char* data;
       int len;
       if (!m->ReadData(iter, &data, &len))
         return false;
       r->SetToBytes(data, len);
     } else {
       DCHECK(type == net::UploadData::TYPE_FILE);
       FilePath file_path;
       uint64 offset, length;
+      base::Time expected_modification_time;
       if (!ReadParam(m, iter, &file_path))
         return false;
       if (!ReadParam(m, iter, &offset))
         return false;
       if (!ReadParam(m, iter, &length))
         return false;
-      r->SetToFilePathRange(file_path, offset, length);
+      if (!ReadParam(m, iter, &expected_modification_time))
+        return false;
+      r->SetToFilePathRange(file_path, offset, length,
+                            expected_modification_time);
     }
     return true;
   }
   static void Log(const param_type& p, std::wstring* l) {
     l->append(L"<net::UploadData::Element>");
   }
 };
 
 // Traits for net::UploadData.
 template <>
@@ skipping 71 matching lines @@
 struct ParamTraits<Geoposition::ErrorCode> {
   typedef Geoposition::ErrorCode 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::wstring* l);
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_COMMON_PARAM_TRAITS_H_