chrome: Update include paths of string_split.h to its new location.

chrome/browser/extensions/api/file_system/file_system_api_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 "base/file_util.h"
 #include "base/files/file_path.h"
-#include "base/string_split.h"
+#include "base/strings/string_split.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
 
 using extensions::FileSystemChooseEntryFunction;
 using extensions::api::file_system::AcceptOption;
 
 namespace {
 
@@ skipping 160 matching lines @@
   // TODO(thorogood): Fix this test on Windows.
   // Filter out absolute paths with no basename.
   opt_name = std::string("/");
   FileSystemChooseEntryFunction::BuildSuggestion(&opt_name, &suggested_name,
       &suggested_extension);
   EXPECT_FALSE(suggested_name.IsAbsolute());
   EXPECT_TRUE(suggested_name.MaybeAsASCII().empty());
   EXPECT_TRUE(suggested_extension.empty());
 #endif
 }