Fixes shutdown race in mash

ash/mus/accelerator_registrar_impl.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 "ash/mus/accelerator_registrar_impl.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "ash/mus/root_window_controller.h"
@@ skipping 17 matching lines @@
 
 AcceleratorRegistrarImpl::AcceleratorRegistrarImpl(
     WindowManager* window_manager,
     uint32_t accelerator_namespace,
     mojo::InterfaceRequest<AcceleratorRegistrar> request,
     const DestroyCallback& destroy_callback)
     : window_manager_(window_manager),
       binding_(this, std::move(request)),
       accelerator_namespace_(accelerator_namespace & 0xffff),
       destroy_callback_(destroy_callback) {
+  window_manager_->AddObserver(this);
   binding_.set_connection_error_handler(base::Bind(
       &AcceleratorRegistrarImpl::OnBindingGone, base::Unretained(this)));
 }
 
 void AcceleratorRegistrarImpl::Destroy() {
   delete this;
 }
 
 bool AcceleratorRegistrarImpl::OwnsAccelerator(uint32_t accelerator_id) const {
   return !!accelerators_.count(accelerator_id);
 }
 
 void AcceleratorRegistrarImpl::ProcessAccelerator(uint32_t accelerator_id,
                                                   const ui::Event& event) {
   DCHECK(OwnsAccelerator(accelerator_id));
   // TODO(moshayedi): crbug.com/617167. Don't clone even once we map
   // mojom::Event directly to ui::Event.
   accelerator_handler_->OnAccelerator(accelerator_id & kAcceleratorIdMask,
                                       ui::Event::Clone(event));
 }
 
 AcceleratorRegistrarImpl::~AcceleratorRegistrarImpl() {
+  window_manager_->RemoveObserver(this);
   RemoveAllAccelerators();
   destroy_callback_.Run(this);
 }
 
 uint32_t AcceleratorRegistrarImpl::ComputeAcceleratorId(
     uint32_t accelerator_id) const {
   return (accelerator_namespace_ << 16) | (accelerator_id & kAcceleratorIdMask);
 }
 
 void AcceleratorRegistrarImpl::OnBindingGone() {
@@ skipping 55 matching lines @@
   window_manager_->window_manager_client()->RemoveAccelerator(
       namespaced_accelerator_id);
 
   // If the registrar is not bound anymore (i.e. the client can no longer
   // install new accelerators), and the last accelerator has been removed, then
   // there's no point keeping this alive anymore.
   if (accelerators_.empty() && !binding_.is_bound())
     delete this;
 }
 
+void AcceleratorRegistrarImpl::OnAccelerator(uint32_t id,
+                                             const ui::Event& event) {
+  if (OwnsAccelerator(id))
+    ProcessAccelerator(id, event);
+}
+
+void AcceleratorRegistrarImpl::OnWindowTreeClientDestroyed() {
+  delete this;
+}
+
 }  // namespace mus
 }  // namespace ash