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

components/tracing/tracing_messages.cc

Index: components/tracing/tracing_messages.cc
diff --git a/components/tracing/tracing_messages.cc b/components/tracing/tracing_messages.cc
index 3d7637ae6b7147129b4e44dabe755c250584abcc..7c6b7897099118384ad4e7e6c08600a1bb6b2374 100644
--- a/components/tracing/tracing_messages.cc
+++ b/components/tracing/tracing_messages.cc
@@ -14,6 +14,12 @@
 #include "ipc/struct_destructor_macros.h"
 #include "components/tracing/tracing_messages.h"
 
+// Generate param traits size methods.
+#include "ipc/param_traits_size_macros.h"
+namespace IPC {
+#include "components/tracing/tracing_messages.h"
+}
+
 // Generate param traits write methods.
 #include "ipc/param_traits_write_macros.h"
 namespace IPC {