Mojo: Report bindings validation errors via MojoNotifyBadMessage

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

 // 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_HEADER_VALIDATOR_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_HEADER_VALIDATOR_H_
 
+#include <string>
+
 #include "mojo/public/cpp/bindings/message.h"
 #include "mojo/public/cpp/bindings/message_filter.h"
 
 namespace mojo {
 namespace internal {
 
 class MessageHeaderValidator : public MessageFilter {
  public:
   explicit MessageHeaderValidator(MessageReceiver* sink = nullptr);
+  MessageHeaderValidator(MessageReceiver* sink, const std::string& debug_info);
 
-  bool Accept(Message* message) override;
+  void set_debug_info(const std::string& debug_info) {
+    debug_info_ = debug_info;
+  }
+
+  Result Accept(Message* message) override;
+
+ private:
+  std::string debug_info_;
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_MESSAGE_HEADER_VALIDATOR_H_