Switch to standard integer types in base/.

BUG=138542
[email protected]
NOPRESUBMIT=true

Review URL: https://codereview.chromium.org/1538743002

Cr-Commit-Position: refs/heads/master@{#366910}
diff --git a/base/bind_internal.h b/base/bind_internal.h
index 947df15..ac7cd00 100644
--- a/base/bind_internal.h
+++ b/base/bind_internal.h
@@ -5,6 +5,8 @@
 #ifndef BASE_BIND_INTERNAL_H_
 #define BASE_BIND_INTERNAL_H_
 
+#include <stddef.h>
+
 #include <type_traits>
 
 #include "base/bind_helpers.h"