mojo::Serialize*_() calls now propogate/return validation errors.

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

Index: mojo/public/cpp/bindings/lib/control_message_handler.cc
diff --git a/mojo/public/cpp/bindings/lib/control_message_handler.cc b/mojo/public/cpp/bindings/lib/control_message_handler.cc
index 0c4698273318675b8a6e245073dd61d978b6eac1..dbc76ef84e6547d343e5d957527098b9e4fafb30 100644
--- a/mojo/public/cpp/bindings/lib/control_message_handler.cc
+++ b/mojo/public/cpp/bindings/lib/control_message_handler.cc
@@ -56,7 +56,9 @@ bool ControlMessageHandler::Run(Message* message,
   ResponseMessageBuilder builder(kRunMessageId, size, message->request_id());
 
   RunResponseMessageParams_Data* response_params = nullptr;
-  Serialize_(response_params_ptr.get(), builder.buffer(), &response_params);
+  MOJO_DCHECK(Serialize_(response_params_ptr.get(), builder.buffer(),
+                         &response_params) ==
+              ValidationError::VALIDATION_ERROR_NONE);
   response_params->EncodePointersAndHandles(
       builder.message()->mutable_handles());
   bool ok = responder->Accept(builder.message());