[ash-md] Corrects a crash when a window is destroyed after leaving overview

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"
@@ skipping 42 matching lines @@
 #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/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"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/widget/native_widget_aura.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/wm/core/window_util.h"
@@ skipping 193 matching lines @@
         GetWindowItemsForRoot(grid_index);
     auto iter = std::find_if(windows.cbegin(), windows.cend(),
                              [window](const WindowSelectorItem* item) {
                                return item->Contains(WmWindowAura::Get(window));
                              });
     if (iter == windows.end())
       return nullptr;
     return *iter;
   }
 
+  gfx::SlideAnimation* GetBackgroundViewAnimationForWindow(
+      int grid_index,
+      aura::Window* window) {
+    return GetWindowItemForWindow(grid_index, window)
+        ->GetBackgroundViewAnimation();
+  }
+
   // Selects |window| in the active overview session by cycling through all
   // windows in overview until it is found. Returns true if |window| was found,
   // false otherwise.
   bool SelectWindow(const aura::Window* window) {
     if (GetSelectedWindow() == nullptr)
       SendKey(ui::VKEY_TAB);
     const aura::Window* start_window = GetSelectedWindow();
     if (start_window == window)
       return true;
     do {
@@ skipping 993 matching lines @@
   }
   {
     ui::ScopedAnimationDurationScaleMode test_duration_mode(
         ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
     ToggleOverview();
     EXPECT_FALSE(window1->IsVisible());
     EXPECT_FALSE(window1->layer()->GetTargetVisibility());
   }
 }
 
+// Tests that it is safe to destroy a window while the overview header animation
+// is still active. See http://crbug.com/646350.
+TEST_P(WindowSelectorTest, SafeToDestroyWindowDuringAnimation) {
+  gfx::Rect bounds(0, 0, 400, 400);
+  {
+    // Quickly enter and exit overview mode to activate header animations.
+    std::unique_ptr<aura::Window> window(CreateWindow(bounds));
+    ui::ScopedAnimationDurationScaleMode test_duration_mode(
+        ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
+    ToggleOverview();
+    EXPECT_TRUE(IsSelecting());
+
+    gfx::SlideAnimation* animation =
+        GetBackgroundViewAnimationForWindow(0, window.get());
+    if (ash::MaterialDesignController::IsOverviewMaterial())
+      ASSERT_TRUE(!!animation);

[sky, 2016/09/15 03:01:00]

Double negatives are hard to read. ASSERT_NE(nullptr, animation) states
intention much better.

[varkha, 2016/09/15 03:54:18]

Done.

+    ToggleOverview();
+    EXPECT_FALSE(IsSelecting());
+    if (animation)
+      EXPECT_TRUE(animation->is_animating());
+
+    // Close the window while the overview header animation is active.
+    window.reset();
+
+    // Progress animation to the end - should not crash.
+    if (animation) {
+      animation->SetCurrentValue(1.0);
+      animation->Reset(1.0);
+    }
+  }
+}
+
 // Tests that a bounds change during overview is corrected for.
 TEST_P(WindowSelectorTest, BoundsChangeDuringOverview) {
   std::unique_ptr<aura::Window> window(CreateWindow(gfx::Rect(0, 0, 400, 400)));
   // Use overview headers above the window in this test.
   window->SetProperty(aura::client::kTopViewInset, 0);
   ToggleOverview();
   gfx::Rect overview_bounds =
       ToEnclosingRect(GetTransformedTargetBounds(window.get()));
   window->SetBounds(gfx::Rect(200, 0, 200, 200));
   gfx::Rect new_overview_bounds =
@@ skipping 847 matching lines @@
       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);
 }
 
 }  // namespace ash