Applied the IconType.

base/callback_old.h

Index: base/callback_old.h
diff --git a/base/callback_old.h b/base/callback_old.h
index ab3927df00dc98f477a14dbf1222b67c09922008..75a062a4aa3a0a1c7dd7c3d1ca8fefd015edb52a 100644
--- a/base/callback_old.h
+++ b/base/callback_old.h
@@ -200,6 +200,22 @@ typename Callback5<Arg1, Arg2, Arg3, Arg4, Arg5>::Type* NewCallback(
       Tuple5<Arg1, Arg2, Arg3, Arg4, Arg5> >(object, method);
 }
 
+// 6-arg implementation
+template <typename Arg1, typename Arg2, typename Arg3,
+          typename Arg4, typename Arg5, typename Arg6>
+struct Callback6 {
+  typedef CallbackRunner<Tuple6<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6> > Type;
+};
+
+template <class T, typename Arg1, typename Arg2, typename Arg3,
+          typename Arg4, typename Arg5, typename Arg6>
+typename Callback6<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6>::Type* NewCallback(
+    T* object,
+    void (T::*method)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6)) {
+  return new CallbackImpl<T, void (T::*)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6),
+      Tuple6<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6> >(object, method);
+}
+
 // An UnboundMethod is a wrapper for a method where the actual object is
 // provided at Run dispatch time.
 template <class T, class Method, class Params>