mus: Unset the cursor client during teardown.

ui/views/mus/desktop_window_tree_host_mus_unittest.cc

 // Copyright 2016 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/views/mus/desktop_window_tree_host_mus.h"
 
 #include "base/memory/ptr_util.h"
+#include "ui/aura/client/cursor_client.h"
 #include "ui/aura/window.h"
 #include "ui/views/test/views_test_base.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 
 namespace views {
 
 class DesktopWindowTreeHostMusTest : public ViewsTestBase {
  public:
   DesktopWindowTreeHostMusTest() {}
   ~DesktopWindowTreeHostMusTest() override {}
 
   // Creates a test widget. Takes ownership of |delegate|.
   std::unique_ptr<Widget> CreateWidget(WidgetDelegate* delegate) {
     std::unique_ptr<Widget> widget = base::MakeUnique<Widget>();
     Widget::InitParams params = CreateParams(Widget::InitParams::TYPE_WINDOW);
     params.delegate = delegate;
     params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
     params.bounds = gfx::Rect(0, 1, 111, 123);
     widget->Init(params);
     return widget;
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostMusTest);
 };
 
+class ExpectsNullCursorClientDuringTearDown : public aura::WindowObserver {
+ public:
+  explicit ExpectsNullCursorClientDuringTearDown(aura::Window* window)
+      : window_(window) {
+    window_->AddObserver(this);
+  }
+
+  ~ExpectsNullCursorClientDuringTearDown() override {
+    EXPECT_FALSE(window_);
+  }
+
+ private:
+  // aura::WindowObserver:
+  void OnWindowRemovingFromRootWindow(aura::Window* window,
+                                      aura::Window* new_root) override {
+    aura::client::CursorClient* cursor_client =
+        aura::client::GetCursorClient(window->GetRootWindow());
+    EXPECT_FALSE(cursor_client);
+    window_->RemoveObserver(this);
+    window_ = nullptr;
+  }
+
+  aura::Window* window_;
+  DISALLOW_COPY_AND_ASSIGN(ExpectsNullCursorClientDuringTearDown);
+};
+
 TEST_F(DesktopWindowTreeHostMusTest, Visibility) {
   std::unique_ptr<Widget> widget(CreateWidget(nullptr));
   EXPECT_FALSE(widget->IsVisible());
   EXPECT_FALSE(widget->GetNativeView()->IsVisible());
   // It's important the parent is also hidden as this value is sent to the
   // server.
   EXPECT_FALSE(widget->GetNativeView()->parent()->IsVisible());
   widget->Show();
   EXPECT_TRUE(widget->IsVisible());
   EXPECT_TRUE(widget->GetNativeView()->IsVisible());
   EXPECT_TRUE(widget->GetNativeView()->parent()->IsVisible());
   widget->Hide();
   EXPECT_FALSE(widget->IsVisible());
   EXPECT_FALSE(widget->GetNativeView()->IsVisible());
   EXPECT_FALSE(widget->GetNativeView()->parent()->IsVisible());
 }
 
+TEST_F(DesktopWindowTreeHostMusTest, CursorClientDuringTearDown) {
+  std::unique_ptr<Widget> widget(CreateWidget(nullptr));
+  widget->Show();
+
+  std::unique_ptr<aura::Window> window(new aura::Window(nullptr));
+  window->Init(ui::LAYER_SOLID_COLOR);
+  ExpectsNullCursorClientDuringTearDown observer(window.get());
+
+  widget->GetNativeWindow()->AddChild(window.release());
+  widget.reset();
+}
+
 }  // namespace views