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

components/pdf/common/pdf_message_generator.cc

Index: components/pdf/common/pdf_message_generator.cc
diff --git a/components/pdf/common/pdf_message_generator.cc b/components/pdf/common/pdf_message_generator.cc
index 025d94c12f74a62db90543ad754d8749d0364ca9..3cd31df7d23e076e6050ef62991da81df953ec13 100644
--- a/components/pdf/common/pdf_message_generator.cc
+++ b/components/pdf/common/pdf_message_generator.cc
@@ -14,6 +14,12 @@
 #include "ipc/struct_destructor_macros.h"
 #include "components/pdf/common/pdf_message_generator.h"
 
+// Generate param traits size methods.
+#include "ipc/param_traits_size_macros.h"
+namespace IPC {
+#include "components/pdf/common/pdf_message_generator.h"
+}
+
 // Generate param traits write methods.
 #include "ipc/param_traits_write_macros.h"
 namespace IPC {