Mojo: Unify the disparate source and header files into 3

mojo/public/bindings/generators/cpp_templates/module_internal.h-template

Index: mojo/public/bindings/generators/cpp_templates/module_internal.h-template
diff --git a/mojo/public/bindings/generators/cpp_templates/interface_serialization.cc-template b/mojo/public/bindings/generators/cpp_templates/module_internal.h-template
similarity index 66%
rename from mojo/public/bindings/generators/cpp_templates/interface_serialization.cc-template
rename to mojo/public/bindings/generators/cpp_templates/module_internal.h-template
index cae063a17c94d2da90ee1aadbb7b255ecbea64c8..2d7ccff70f70747c81bf1cb59db259bcea2426b4 100644
--- a/mojo/public/bindings/generators/cpp_templates/interface_serialization.cc-template
+++ b/mojo/public/bindings/generators/cpp_templates/module_internal.h-template
@@ -2,20 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "$HEADER"
-
-namespace $NAMESPACE {
-namespace internal {
-
-$IMPLEMENTATIONS
+#ifndef $HEADER_GUARD
+#define $HEADER_GUARD
 
-}  // namespace internal
-}  // namespace sample
+#include "mojo/public/bindings/lib/bindings_serialization.h"
+#include "$HEADER"
 
 namespace mojo {
 namespace internal {
 
-$SERIALIZATIONS
+$TRAITS
 
 }  // namespace internal
 }  // namespace mojo
+
+#endif  // $HEADER_GUARD