Update the remaining include paths of base/string_piece.h to its new location.

chrome_frame/test/test_server.cc

 // Copyright (c) 2012 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.
 
 #include "chrome_frame/test/test_server.h"
 
 #include <windows.h>
 #include <objbase.h>
 #include <urlmon.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
-#include "base/string_piece.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
+#include "base/strings/string_piece.h"
 #include "base/utf_string_conversions.h"
 #include "chrome_frame/test/chrome_frame_test_utils.h"
 #include "net/base/winsock_init.h"
 #include "net/http/http_util.h"
 #include "net/socket/tcp_listen_socket.h"
 
 namespace test_server {
 const char kDefaultHeaderTemplate[] =
     "HTTP/1.1 %hs\r\n"
     "Connection: close\r\n"
@@ skipping 384 matching lines @@
     data_.append(content_length_header);
     data_.append("\r\n");
   }
 
   MessageLoop::current()->PostDelayedTask(
       FROM_HERE, base::Bind(&ConfigurableConnection::SendChunk, this),
       base::TimeDelta::FromMilliseconds(options.timeout_));
 }
 
 }  // namespace test_server