chromeos: makes it possible for windows to outlive WindowTreeClient

ui/aura/env.cc

 // Copyright (c) 2012 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 "ui/aura/env.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/memory/ptr_util.h"
 #include "base/threading/thread_local.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env_input_state_controller.h"
 #include "ui/aura/env_observer.h"
 #include "ui/aura/input_state_lookup.h"
 #include "ui/aura/local/window_port_local.h"
 #include "ui/aura/mus/mus_types.h"
 #include "ui/aura/mus/os_exchange_data_provider_mus.h"
 #include "ui/aura/mus/window_port_mus.h"
 #include "ui/aura/mus/window_tree_client.h"
 #include "ui/aura/window.h"
+#include "ui/aura/window_port_for_shutdown.h"
 #include "ui/events/event_target_iterator.h"
 #include "ui/events/platform/platform_event_source.h"
 
 #if defined(USE_OZONE)
 #include "ui/ozone/public/client_native_pixmap_factory_ozone.h"
 #include "ui/ozone/public/ozone_platform.h"
 #endif
 
 namespace aura {
 
@@ skipping 45 matching lines @@
 
 // static
 Env* Env::GetInstanceDontCreate() {
   return lazy_tls_ptr.Pointer()->Get();
 }
 
 std::unique_ptr<WindowPort> Env::CreateWindowPort(Window* window) {
   if (mode_ == Mode::LOCAL)
     return base::MakeUnique<WindowPortLocal>(window);
 
+  if (in_mus_shutdown_)
+    return base::MakeUnique<WindowPortForShutdown>();
+
   DCHECK(window_tree_client_);
   WindowMusType window_mus_type;
   switch (window->GetProperty(aura::client::kEmbedType)) {
     case aura::client::WindowEmbedType::NONE:
       window_mus_type = WindowMusType::LOCAL;
       break;
     case aura::client::WindowEmbedType::TOP_LEVEL_IN_WM:
       window_mus_type = WindowMusType::TOP_LEVEL_IN_WM;
       break;
     case aura::client::WindowEmbedType::EMBED_IN_OWNER:
@@ skipping 19 matching lines @@
       mouse_button_flags_ != 0;
 }
 
 const gfx::Point& Env::last_mouse_location() const {
   if (mode_ == Mode::LOCAL || always_use_last_mouse_location_ ||
       !get_last_mouse_location_from_mus_) {
     return last_mouse_location_;
   }
 
   // Some tests may not install a WindowTreeClient, and we allow multiple
-  // WindowTreeClients for the case of multiple connections.
+  // WindowTreeClients for the case of multiple connections, and this may be
+  // called during shutdown, when there is no WindowTreeClient.
   if (window_tree_client_)
     last_mouse_location_ = window_tree_client_->GetCursorScreenPoint();
   return last_mouse_location_;
 }
 
 void Env::SetWindowTreeClient(WindowTreeClient* window_tree_client) {
   // The WindowTreeClient should only be set once. Test code may need to change
   // the value after the fact, to do that use EnvTestHelper.
   DCHECK(!window_tree_client_);
   window_tree_client_ = window_tree_client;
@@ skipping 54 matching lines @@
 void Env::NotifyHostInitialized(WindowTreeHost* host) {
   for (EnvObserver& observer : observers_)
     observer.OnHostInitialized(host);
 }
 
 void Env::NotifyHostActivated(WindowTreeHost* host) {
   for (EnvObserver& observer : observers_)
     observer.OnHostActivated(host);
 }
 
+void Env::WindowTreeClientDestroyed(aura::WindowTreeClient* client) {
+  DCHECK_EQ(Mode::MUS, mode_);
+
+  if (client != window_tree_client_)
+    return;
+
+  in_mus_shutdown_ = true;
+  window_tree_client_ = nullptr;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Env, ui::EventTarget implementation:
 
 bool Env::CanAcceptEvent(const ui::Event& event) {
   return true;
 }
 
 ui::EventTarget* Env::GetParentTarget() {
   return NULL;
 }
 
 std::unique_ptr<ui::EventTargetIterator> Env::GetChildIterator() const {
   return nullptr;
 }
 
 ui::EventTargeter* Env::GetEventTargeter() {
   NOTREACHED();
   return NULL;
 }
 
 std::unique_ptr<ui::OSExchangeData::Provider> Env::BuildProvider() {
   return base::MakeUnique<aura::OSExchangeDataProviderMus>();
 }
 
 }  // namespace aura