Mojo cpp bindings: add support for validating incoming messages.

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

Index: mojo/public/cpp/bindings/lib/interface_impl_internal.h
diff --git a/mojo/public/cpp/bindings/lib/interface_impl_internal.h b/mojo/public/cpp/bindings/lib/interface_impl_internal.h
index 50fe5665360b3f6bd11950503b52311d16592eaa..2dd869ff85dde918daed281ca6d7d13b9fb0bc45 100644
--- a/mojo/public/cpp/bindings/lib/interface_impl_internal.h
+++ b/mojo/public/cpp/bindings/lib/interface_impl_internal.h
@@ -7,6 +7,8 @@
 
 #include "mojo/public/cpp/bindings/error_handler.h"
 #include "mojo/public/cpp/bindings/interface_ptr.h"
+#include "mojo/public/cpp/bindings/lib/message_header_validator.h"
+#include "mojo/public/cpp/bindings/lib/validator_chain.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
@@ -42,7 +44,12 @@ class InterfaceImplState : public ErrorHandler {
             MojoAsyncWaiter* waiter) {
     assert(!router_);
 
-    router_ = new Router(handle.Pass(), waiter);
+    internal::ValidatorChain validators;
+    validators.Append(new internal::MessageHeaderValidator)
+              .Append(new typename Interface::RequestValidator_)
+              .Append(new typename Interface::Client_::ResponseValidator_);
+
+    router_ = new Router(handle.Pass(), validators.Pass(), waiter);
     router_->set_incoming_receiver(&stub_);
     router_->set_error_handler(this);