Fixes shutdown race in mash

ash/mus/window_manager_application.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/window_manager_application.h"
 
 #include <utility>
 
 #include "ash/mus/accelerator_registrar_impl.h"
 #include "ash/mus/root_window_controller.h"
-#include "ash/mus/root_windows_observer.h"
 #include "ash/mus/shelf_layout_impl.h"
 #include "ash/mus/user_window_controller_impl.h"
 #include "ash/mus/window_manager.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "components/mus/common/event_matcher_util.h"
 #include "components/mus/common/gpu_service.h"
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/cpp/window_tree_client.h"
 #include "services/shell/public/cpp/connection.h"
@@ skipping 14 matching lines @@
   std::set<AcceleratorRegistrarImpl*> accelerator_registrars(
       accelerator_registrars_);
   for (AcceleratorRegistrarImpl* registrar : accelerator_registrars)
     registrar->Destroy();
 
   // Destroy the WindowManager while still valid. This way we ensure
   // OnWillDestroyRootWindowController() is called (if it hasn't been already).
   window_manager_.reset();
 }
 
-void WindowManagerApplication::OnAccelerator(uint32_t id,
-                                             const ui::Event& event) {
-  for (auto* registrar : accelerator_registrars_) {
-    if (registrar->OwnsAccelerator(id)) {
-      registrar->ProcessAccelerator(id, event);
-      break;
-    }
-  }
-}
-
 void WindowManagerApplication::OnAcceleratorRegistrarDestroyed(
     AcceleratorRegistrarImpl* registrar) {
   accelerator_registrars_.erase(registrar);
 }
 
 void WindowManagerApplication::InitWindowManager(
     ::mus::WindowTreeClient* window_tree_client) {
   window_manager_->Init(window_tree_client);
-  window_manager_->AddRootWindowsObserver(this);
+  window_manager_->AddObserver(this);
 }
 
 void WindowManagerApplication::Initialize(shell::Connector* connector,
                                           const shell::Identity& identity,
                                           uint32_t id) {
   connector_ = connector;
   ::mus::GpuService::Initialize(connector);
-  window_manager_.reset(new WindowManager(this, connector_));
+  window_manager_.reset(new WindowManager(connector_));
 
   aura_init_.reset(new views::AuraInit(connector_, "ash_mus_resources.pak"));
 
   tracing_.Initialize(connector, identity.name());
 
   ::mus::WindowTreeClient* window_tree_client = new ::mus::WindowTreeClient(
       window_manager_.get(), window_manager_.get(), nullptr);
   window_tree_client->ConnectAsWindowManager(connector);
 
   InitWindowManager(window_tree_client);
@@ skipping 32 matching lines @@
   } else {
     user_window_controller_requests_.push_back(base::WrapUnique(
         new mojo::InterfaceRequest<mojom::UserWindowController>(
             std::move(request))));
   }
 }
 
 void WindowManagerApplication::Create(
     shell::Connection* connection,
     mojo::InterfaceRequest<::mus::mojom::AcceleratorRegistrar> request) {
+  if (!window_manager_->window_manager_client())
+    return;  // Can happen during shutdown.
+
   static int accelerator_registrar_count = 0;
   if (accelerator_registrar_count == std::numeric_limits<int>::max()) {
     // Restart from zero if we have reached the limit. It is technically
     // possible to end up with multiple active registrars with the same
     // namespace, but it is highly unlikely. In the event that multiple
     // registrars have the same namespace, this new registrar will be unable to
     // install accelerators.
     accelerator_registrar_count = 0;
   }
   accelerator_registrars_.insert(new AcceleratorRegistrarImpl(
@@ skipping 36 matching lines @@
     RootWindowController* controller) {
   // TODO(msw): this isn't right, ownership should belong in WindowManager
   // and/or RootWindowController. But this is temporary until we get rid of
   // sysui.
   shelf_layout_.reset();
   user_window_controller_.reset();
 }
 
 }  // namespace mus
 }  // namespace ash