Move FileEnumerator to its own file, do some refactoring.

chrome/test/perf/startup_test.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/environment.h"
 #include "base/file_util.h"
+#include "base/files/file_enumerator.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/sys_info.h"
 #include "base/test/test_file_util.h"
 #include "base/test/test_timeouts.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
@@ skipping 450 matching lines @@
 }
 
 TEST_F(StartupTest, ProfilingScript1) {
   SetUpWithFileURL();
   SetUpWithProfiling();
   RunStartupTest("warm", "profiling_scripts1", WARM, NOT_IMPORTANT,
                  UITestBase::DEFAULT_THEME, 1, 0);
 }
 
 }  // namespace