run iwyu on base!

base/file_util.cc

Index: base/file_util.cc
diff --git a/base/file_util.cc b/base/file_util.cc
index c9661e714d2ffcfdb0fccd56b56e7e9488b08e69..f29f6f36fcdd3b692fffc109824d46ddeaeffdf3 100644
--- a/base/file_util.cc
+++ b/base/file_util.cc
@@ -2,20 +2,24 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/basictypes.h"
 #include "base/file_util.h"
+#include "base/platform_file.h"
 
 #if defined(OS_WIN)
 #include <io.h>
 #endif
 #include <stdio.h>
-
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
 #include <fstream>
+#include <ios>
+#include <string>
 
 #include "base/file_path.h"
 #include "base/logging.h"
-#include "base/string_piece.h"
 #include "base/string_util.h"
-#include "base/utf_string_conversions.h"
 
 namespace {