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

chrome/common/render_messages.h

Index: chrome/common/render_messages.h
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 9f01811fa967cb9cb094720743a8964b4d4ab5b6..0d232859c36368206989de0985017081d13643c3 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -50,6 +50,7 @@ namespace IPC {
 template <>
 struct ParamTraits<ContentSettingsPattern> {
   typedef ContentSettingsPattern param_type;
+  static void GetSize(base::PickleSizer* s, const param_type& p);
   static void Write(base::Pickle* m, const param_type& p);
   static bool Read(const base::Pickle* m,
                    base::PickleIterator* iter,