CPP bindings: DCHECK when a Callback is destructed without being invoked

mojo/public/cpp/bindings/lib/router.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/router.h"
 
 #include "mojo/public/cpp/environment/logging.h"
 
 namespace mojo {
 namespace internal {
 
 // ----------------------------------------------------------------------------
 
-class ResponderThunk : public MessageReceiver {
+class ResponderThunk : public MessageReceiverWithStatus {
  public:
   explicit ResponderThunk(const SharedData<Router*>& router)
       : router_(router), accept_was_invoked_(false) {}
   ~ResponderThunk() override {
     if (!accept_was_invoked_) {
       // The Mojo application handled a message that was expecting a response
       // but did not send a response.
       Router* router = router_.value();
       if (router) {
         // We close the pipe here as a way of signaling to the calling
@@ skipping 12 matching lines @@
 
     bool result = false;
 
     Router* router = router_.value();
     if (router)
       result = router->Accept(message);
 
     return result;
   }
 
+  // MessageReceiverWithStatus implementation:
+  bool IsValid() override {
+    Router* router = router_.value();
+    return router && !router->encountered_error() && router->is_valid();
+  }
+
  private:
   SharedData<Router*> router_;
   bool accept_was_invoked_;
 };
 
 // ----------------------------------------------------------------------------
 
 Router::HandleIncomingMessageThunk::HandleIncomingMessageThunk(Router* router)
     : router_(router) {
 }
@@ skipping 54 matching lines @@
 }
 
 void Router::EnableTestingMode() {
   testing_mode_ = true;
   connector_.set_enforce_errors_from_incoming_receiver(false);
 }
 
 bool Router::HandleIncomingMessage(Message* message) {
   if (message->has_flag(kMessageExpectsResponse)) {
     if (incoming_receiver_) {
-      MessageReceiver* responder = new ResponderThunk(weak_self_);
+      MessageReceiverWithStatus* responder = new ResponderThunk(weak_self_);
       bool ok = incoming_receiver_->AcceptWithResponder(message, responder);
       if (!ok)
         delete responder;
       return ok;
     }
 
     // If we receive a request expecting a response when the client is not
     // listening, then we have no choice but to tear down the pipe.
     connector_.CloseMessagePipe();
   } else if (message->has_flag(kMessageIsResponse)) {
@@ skipping 14 matching lines @@
     // OK to drop message on the floor.
   }
 
   return false;
 }
 
 // ----------------------------------------------------------------------------
 
 }  // namespace internal
 }  // namespace mojo