Mojo C++ bindings: make InterfaceEndpointClient observe message loop destruction.

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

 // Copyright 2015 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/interface_endpoint_client.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 141 matching lines @@
 
   // TODO(yzshen): the way to use validator (or message filter in general)
   // directly is a little awkward.
   if (payload_validator)
     filters_.Append(std::move(payload_validator));
 
   controller_ = handle_.group_controller()->AttachEndpointClient(
       handle_, this, task_runner_);
   if (expect_sync_requests)
     controller_->AllowWokenUpBySyncWatchOnSameThread();
+
+  base::MessageLoop::current()->AddDestructionObserver(this);
 }
 
 InterfaceEndpointClient::~InterfaceEndpointClient() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  StopObservingIfNecessary();
+
   if (handle_.is_valid())
     handle_.group_controller()->DetachEndpointClient(handle_);
 }
 
 AssociatedGroup* InterfaceEndpointClient::associated_group() {
   if (!associated_group_)
     associated_group_ = handle_.group_controller()->CreateAssociatedGroup();
   return associated_group_.get();
 }
 
@@ skipping 152 matching lines @@
     async_responders_.erase(it);
     return responder->Accept(message);
   } else {
     if (mojo::internal::ControlMessageHandler::IsControlMessage(message))
       return control_message_handler_.Accept(message);
 
     return incoming_receiver_->Accept(message);
   }
 }
 
+void InterfaceEndpointClient::StopObservingIfNecessary() {
+  if (!observing_message_loop_destruction_)
+    return;
+
+  observing_message_loop_destruction_ = false;
+  base::MessageLoop::current()->RemoveDestructionObserver(this);
+}
+
+void InterfaceEndpointClient::WillDestroyCurrentMessageLoop() {
+  StopObservingIfNecessary();
+  NotifyError();
+}
+
 }  // namespace mojo