Mojo cpp bindings: add support for validating incoming messages.

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/public/cpp/bindings/lib/message_header_validator.h"
 
 #include "mojo/public/cpp/bindings/lib/bindings_serialization.h"
 
 namespace mojo {
 namespace internal {
@@ skipping 36 matching lines @@
   // These flags are mutually exclusive.
   if ((header->flags & internal::kMessageExpectsResponse) &&
       (header->flags & internal::kMessageIsResponse))
     return false;
 
   return true;
 }
 
 }  // namespace
 
-MessageHeaderValidator::MessageHeaderValidator(MessageReceiver* next)
-    : next_(next) {
-  assert(next);
+MessageHeaderValidator::MessageHeaderValidator(MessageReceiver* sink)
+    : MessageFilter(sink) {
 }
 
 bool MessageHeaderValidator::Accept(Message* message) {
   // Make sure the message header isn't truncated before we start to read it.
   if (message->data_num_bytes() < sizeof(internal::MessageHeader) ||
       message->data_num_bytes() < message->header()->num_bytes) {
     return false;
   }
 
   if (!IsValidMessageHeader(message->header()))
     return false;
 
-  return next_->Accept(message);
-}
-
-bool MessageHeaderValidator::AcceptWithResponder(Message* message,
-                                                 MessageReceiver* responder) {
-  assert(false);  // Not reached!
-  return false;
+  return sink_->Accept(message);
 }
 
 }  // namespace internal
 }  // namespace mojo