[ash-md] Prevents a crash when entering overview mode while dragging a window

ash/wm/overview/window_selector_unittest.cc

 // Copyright 2013 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 <algorithm>
 #include <vector>
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/accessibility_delegate.h"
 #include "ash/common/accessibility_types.h"
 #include "ash/common/ash_switches.h"
 #include "ash/common/shelf/shelf_widget.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/wm/dock/docked_window_layout_manager.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm/mru_window_tracker.h"
 #include "ash/common/wm/overview/scoped_transform_overview_window.h"
 #include "ash/common/wm/overview/window_grid.h"
 #include "ash/common/wm/overview/window_selector.h"
 #include "ash/common/wm/overview/window_selector_controller.h"
 #include "ash/common/wm/overview/window_selector_item.h"
 #include "ash/common/wm/panels/panel_layout_manager.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm/wm_event.h"
+#include "ash/common/wm/workspace/workspace_window_resizer.h"
 #include "ash/common/wm_lookup.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window_property.h"
 #include "ash/display/display_manager.h"
 #include "ash/drag_drop/drag_drop_controller.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
@@ skipping 11 matching lines @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/user_action_tester.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/test/test_windows.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
+#include "ui/base/hit_test.h"
 #include "ui/compositor/scoped_animation_duration_scale_mode.h"
 #include "ui/display/manager/display_layout.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/test/event_generator.h"
 #include "ui/gfx/animation/slide_animation.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/geometry/safe_integer_conversions.h"
 #include "ui/gfx/transform.h"
 #include "ui/gfx/transform_util.h"
@@ skipping 1943 matching lines @@
       transformed_rect.y() + gfx::ToCeiledInt(scale * inset) - header_height,
       bounds.y());
   EXPECT_LE(transformed_rect.bottom(), bounds.bottom());
   EXPECT_NEAR(transformed_rect.x() - bounds.x(),
               bounds.right() - transformed_rect.right(), 1);
   EXPECT_NEAR(
       transformed_rect.y() + (int)(scale * inset) - header_height - bounds.y(),
       bounds.bottom() - transformed_rect.bottom(), 1);
 }
 
+// Start dragging a window and activate overview mode. This test should not
+// crash or DCHECK inside aura::Window::StackChildRelativeTo().
+TEST_F(WindowSelectorTest, OverviewWhileDragging) {
+  const gfx::Rect bounds(10, 10, 100, 100);
+  std::unique_ptr<aura::Window> window(CreateWindow(bounds));
+  std::unique_ptr<WindowResizer> resizer(
+      CreateWindowResizer(WmWindowAura::Get(window.get()), gfx::Point(),
+                          HTCAPTION, aura::client::WINDOW_MOVE_SOURCE_MOUSE));
+  ASSERT_TRUE(resizer.get());
+  gfx::Point location = resizer->GetInitialLocation();
+  location.Offset(20, 20);
+  resizer->Drag(location, 0);
+  ToggleOverview();
+  resizer->RevertDrag();
+}
+
 }  // namespace ash