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

webkit/fileapi/file_system_url_request_job_unittest.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 "webkit/fileapi/file_system_url_request_job.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/format_macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/platform_file.h"
 #include "base/rand_util.h"
-#include "base/string_piece.h"
 #include "base/stringprintf.h"
+#include "base/strings/string_piece.h"
 #include "base/utf_string_conversions.h"
 #include "net/base/load_flags.h"
 #include "net/base/mime_util.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_util.h"
 #include "net/http/http_request_headers.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 329 matching lines @@
 
   TestRequest(CreateFileSystemURL(kFilename));
 
   std::string mime_type_from_job;
   request_->GetMimeType(&mime_type_from_job);
   EXPECT_EQ(mime_type_direct, mime_type_from_job);
 }
 
 }  // namespace
 }  // namespace fileapi