run iwyu on base!

base/string_util.cc

Index: base/string_util.cc
diff --git a/base/string_util.cc b/base/string_util.cc
index ce12705b4ea07b260cda45088fb1eb34f9b35c4b..497fcfd847f67a5479f3363ce0eb089f67bdc7df 100644
--- a/base/string_util.cc
+++ b/base/string_util.cc
@@ -2,31 +2,24 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/string_util.h"
-
-#include "build/build_config.h"
-
-#include <ctype.h>
-#include <errno.h>
-#include <math.h>
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
+#include <i386/types.h>
+#include <stdbool.h>
+#include <stddef.h>
 #include <wchar.h>
-#include <wctype.h>
-
 #include <algorithm>
+#include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/singleton.h"
-#include "base/third_party/dmg_fp/dmg_fp.h"
+#include "base/string16.h"
+#include "base/string_piece.h"
+#include "base/string_util.h"
+#include "base/string_util_posix.h"
+#include "base/third_party/icu/icu_utf.h"
 #include "base/utf_string_conversion_utils.h"
 #include "base/utf_string_conversions.h"
-#include "base/third_party/icu/icu_utf.h"
 
 namespace {