Generate param traits size methods for IPC files in chrome/ (and traits it depends on).

ipc/ipc_message_utils.h

Index: ipc/ipc_message_utils.h
diff --git a/ipc/ipc_message_utils.h b/ipc/ipc_message_utils.h
index 0de489bfb38c8bd982a0639f5b25855d35a90751..98485493511f279822dcf4a0907a041187a13969 100644
--- a/ipc/ipc_message_utils.h
+++ b/ipc/ipc_message_utils.h
@@ -992,6 +992,7 @@ struct ParamTraits<std::unique_ptr<P>> {
 template<>
 struct IPC_EXPORT ParamTraits<IPC::ChannelHandle> {
   typedef ChannelHandle param_type;
+  static void GetSize(base::PickleSizer* sizer, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,