Support sending a sliced file in chromium....

net/url_request/url_request.h

 // Copyright (c) 2006-2009 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.
 
 #ifndef NET_URL_REQUEST_URL_REQUEST_H_
 #define NET_URL_REQUEST_URL_REQUEST_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 281 matching lines @@
 
   // The data comprising the request message body is specified as a sequence of
   // data segments and/or files containing data to upload.  These methods may
   // be called to construct the data sequence to upload, and they may only be
   // called before Start() is called.  For POST requests, the user must call
   // SetRequestHeaderBy{Id,Name} to set the Content-Type of the request to the
   // appropriate value before calling Start().
   //
   // When uploading data, bytes_len must be non-zero.
   // When uploading a file range, length must be non-zero. If length
-  // exceeds the end-of-file, the upload is clipped at end-of-file.
+  // exceeds the end-of-file, the upload is clipped at end-of-file. If the
+  // expected modification time is provided (non-zero), it will be used to
+  // check if the underlying file has been changed or not. The granularity of
+  // the time comparison is 1 second since time_t precision is used in WebKit.
   void AppendBytesToUpload(const char* bytes, int bytes_len);
   void AppendFileRangeToUpload(const FilePath& file_path,
-                               uint64 offset, uint64 length);
+                               uint64 offset, uint64 length,
+                               const base::Time& expected_modification_time);
   void AppendFileToUpload(const FilePath& file_path) {
-    AppendFileRangeToUpload(file_path, 0, kuint64max);
+    AppendFileRangeToUpload(file_path, 0, kuint64max, base::Time());
   }
 
   // Set the upload data directly.
   void set_upload(net::UploadData* upload);
 
   // Get the upload data directly.
   net::UploadData* get_upload();
 
   // Returns true if the request has a non-empty message body to upload.
   bool has_upload() const;
@@ skipping 305 matching lines @@
   // The priority level for this request.  Objects like ClientSocketPool use
   // this to determine which URLRequest to allocate sockets to first.
   net::RequestPriority priority_;
 
   base::LeakTracker<URLRequest> leak_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequest);
 };
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_H_