Mojo C++ bindings: switch the remaining callsites of the old serialization interface.

mojo/public/cpp/bindings/lib/control_message_handler.h

Index: mojo/public/cpp/bindings/lib/control_message_handler.h
diff --git a/mojo/public/cpp/bindings/lib/control_message_handler.h b/mojo/public/cpp/bindings/lib/control_message_handler.h
index 27acde8cbdf4232dc683089f1836b96da90448ac..13b5aa6214ea5e08b07cc057e8638ba0f02ad0a1 100644
--- a/mojo/public/cpp/bindings/lib/control_message_handler.h
+++ b/mojo/public/cpp/bindings/lib/control_message_handler.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include "base/macros.h"
+#include "mojo/public/cpp/bindings/lib/serialization_context.h"
 #include "mojo/public/cpp/bindings/message.h"
 
 namespace mojo {
@@ -32,6 +33,7 @@ class ControlMessageHandler : public MessageReceiverWithResponderStatus {
   bool RunOrClosePipe(Message* message);
 
   uint32_t interface_version_;
+  SerializationContext context_;
 
   DISALLOW_COPY_AND_ASSIGN(ControlMessageHandler);
 };