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

components/nacl/common/nacl_host_messages.cc

Index: components/nacl/common/nacl_host_messages.cc
diff --git a/components/nacl/common/nacl_host_messages.cc b/components/nacl/common/nacl_host_messages.cc
index 1b4727244dfa963e0d45bdfc0d313bae4ad15ce6..37d6db62876c61c55421ac514b5bd24956867ecf 100644
--- a/components/nacl/common/nacl_host_messages.cc
+++ b/components/nacl/common/nacl_host_messages.cc
@@ -14,6 +14,12 @@
 #include "ipc/struct_destructor_macros.h"
 #include "components/nacl/common/nacl_host_messages.h"
 
+// Generate param traits size methods.
+#include "ipc/param_traits_size_macros.h"
+namespace IPC {
+#include "components/nacl/common/nacl_host_messages.h"
+}
+
 // Generate param traits write methods.
 #include "ipc/param_traits_write_macros.h"
 namespace IPC {