cros: Reset should_animate_when_entering_ for overview animations

WindowGrid::PositionWindows is called at multiple places to animate
windows in overview mode. Reset the should_animate_when_entering_ flag
in order to animate in other situations.

Bug: 817888
Test: WindowSelectorTest.WindowItemCanAnimateOnDragRelease
Change-Id: I14a773033982c47823e6a0e331b7b8df4baa1791
Reviewed-on: https://chromium-review.googlesource.com/952671
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541689}

ash/wm/overview/window_grid.cc

@@ -729,6 +729,11 @@ void WindowGrid::SetWindowListAnimationStates(
   }
 }
 
+void WindowGrid::ResetWindowListAnimationStates() {
+  for (const auto& selector_item : window_list_)
+    selector_item->ResetAnimationStates();
+}
+
 void WindowGrid::InitShieldWidget() {
   // TODO(varkha): The code assumes that SHELF_BACKGROUND_MAXIMIZED is
   // synonymous with a black shelf background. Update this code if that

ash/wm/overview/window_grid.h

@@ -182,6 +182,10 @@ class ASH_EXPORT WindowGrid : public aura::WindowObserver,
       WindowSelectorItem* selected_item,
       WindowSelector::OverviewTransition transition);
 
+  // Reset |selector_item|'s |should_animate_when_entering_|,
+  // |should_animate_when_exiting_| and |should_be_observed_when_exiting_|.
+  void ResetWindowListAnimationStates();
+
  private:
   class ShieldView;
   friend class WindowSelectorTest;

ash/wm/overview/window_selector.cc

@@ -308,6 +308,10 @@ void WindowSelector::Init(const WindowList& windows,
       }
       window_grid->PrepareForOverview();
       window_grid->PositionWindows(/*animate=*/true);
+      // Reset |should_animate_when_entering_| in order to animate during
+      // overview mode, such as dragging animations.
+      if (IsNewOverviewAnimationsEnabled())
+        window_grid->ResetWindowListAnimationStates();
     }
 
     // Image used for text filter textfield.

ash/wm/overview/window_selector_item.cc

@@ -1010,6 +1010,12 @@ bool WindowSelectorItem::ShouldBeObservedWhenExiting() const {
   return should_be_observed_when_exiting_;
 }
 
+void WindowSelectorItem::ResetAnimationStates() {
+  should_animate_when_entering_ = true;
+  should_animate_when_exiting_ = true;
+  should_be_observed_when_exiting_ = false;
+}
+
 OverviewAnimationType WindowSelectorItem::GetExitOverviewAnimationType() {
   return ShouldAnimateWhenExiting()
              ? OverviewAnimationType::OVERVIEW_ANIMATION_LAY_OUT_SELECTOR_ITEMS

ash/wm/overview/window_selector_item.h

@@ -198,6 +198,8 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   }
   bool ShouldBeObservedWhenExiting() const;
 
+  void ResetAnimationStates();
+
   OverviewAnimationType GetExitOverviewAnimationType();
   OverviewAnimationType GetExitTransformAnimationType();
 

ash/wm/overview/window_selector_unittest.cc

@@ -2164,21 +2164,13 @@ TEST_F(WindowSelectorTest, SetWindowListAnimationStates) {
   EXPECT_TRUE(wm::GetWindowState(window2.get())->IsFullscreen());
   EXPECT_TRUE(wm::GetWindowState(window3.get())->IsFullscreen());
 
+  ui::ScopedAnimationDurationScaleMode test_duration_mode(
+      ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
   // Enter overview.
   ToggleOverview();
-
-  const int grid_index = 0;
-  WindowSelectorItem* selector_item1 =
-      GetWindowItemForWindow(grid_index, window1.get());
-  WindowSelectorItem* selector_item2 =
-      GetWindowItemForWindow(grid_index, window2.get());
-  WindowSelectorItem* selector_item3 =
-      GetWindowItemForWindow(grid_index, window3.get());
-
-  // All the animation states during entering overview are correctly updated.
-  EXPECT_TRUE(selector_item1->ShouldAnimateWhenEntering());
-  EXPECT_TRUE(selector_item2->ShouldAnimateWhenEntering());
-  EXPECT_FALSE(selector_item3->ShouldAnimateWhenEntering());
+  EXPECT_TRUE(window1->layer()->GetAnimator()->is_animating());
+  EXPECT_TRUE(window2->layer()->GetAnimator()->is_animating());
+  EXPECT_FALSE(window3->layer()->GetAnimator()->is_animating());
 
   ToggleOverview();
 }
@@ -2515,6 +2507,36 @@ TEST_F(WindowSelectorTest, DISABLED_HandleAlwaysOnTopWindow) {
   RunAllPendingInMessageLoop();
 }
 
+// Verify that the selector item can animate after the item is dragged and
+// released.
+TEST_F(WindowSelectorTest, WindowItemCanAnimateOnDragRelease) {
+  UpdateDisplay("400x400");
+  const gfx::Rect bounds(10, 10, 200, 200);
+  std::unique_ptr<aura::Window> window1(CreateWindow(bounds));
+  std::unique_ptr<aura::Window> window2(CreateWindow(bounds));
+  wm::ActivateWindow(window2.get());
+  wm::ActivateWindow(window1.get());
+
+  // The item dragging is only allowed in tablet mode.
+  RunAllPendingInMessageLoop();
+  Shell::Get()->tablet_mode_controller()->EnableTabletModeWindowManager(true);
+
+  ToggleOverview();
+  WindowSelectorItem* item2 = GetWindowItemForWindow(0, window2.get());
+  // Drag |item2| in a way so that |window2| does not get activated.
+  GetEventGenerator().MoveMouseTo(item2->target_bounds().CenterPoint());
+  GetEventGenerator().PressLeftButton();
+  RunAllPendingInMessageLoop();
+
+  GetEventGenerator().MoveMouseTo(gfx::Point(200, 200));
+  ui::ScopedAnimationDurationScaleMode test_duration_mode(
+      ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
+  GetEventGenerator().ReleaseLeftButton();
+  EXPECT_TRUE(window2->layer()->GetAnimator()->IsAnimatingProperty(
+      ui::LayerAnimationElement::AnimatableProperty::TRANSFORM));
+  RunAllPendingInMessageLoop();
+}
+
 // Verify that the window selector items titlebar and close button change
 // visibility when a item is being dragged.
 TEST_F(WindowSelectorTest, WindowItemTitleCloseVisibilityOnDrag) {