Switch to standard integer types in chrome/browser/, part 2 of 4.

chrome/browser/external_extension_browsertest.cc

Index: chrome/browser/external_extension_browsertest.cc
diff --git a/chrome/browser/external_extension_browsertest.cc b/chrome/browser/external_extension_browsertest.cc
index a9c216414a003c63f41d69cda01b1c7f3db05897..54eb79b71335eed178a2c984e87ee4b527d44c31 100644
--- a/chrome/browser/external_extension_browsertest.cc
+++ b/chrome/browser/external_extension_browsertest.cc
@@ -2,10 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <stddef.h>
+
 #include "base/command_line.h"
+#include "base/macros.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "build/build_config.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"