overview gesture: start drag window only when hotseat has dragged up.

Bug: 997885
Change-Id: I8d4c918b51ff5a2bad566471ca9edb34e680a890
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1900279Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713111}

ash/shelf/shelf_layout_manager.cc

@@ -2164,7 +2164,6 @@ bool ShelfLayoutManager::StartShelfDrag(
                               : SHELF_AUTO_HIDE_SHOWN;
   MaybeSetupHotseatDrag(event_in_screen);
   MaybeUpdateShelfBackground(AnimationChangeType::ANIMATE);
-  MaybeStartDragWindowFromShelf(event_in_screen);
 
   // For the hotseat, |drag_amount_| is relative to the top of the shelf.
   // To keep the hotseat from jumping to the top of the shelf on drag, set the
@@ -2176,6 +2175,9 @@ bool ShelfLayoutManager::StartShelfDrag(
   } else {
     drag_amount_ = 0.f;
   }
+
+  MaybeStartDragWindowFromShelf(event_in_screen);
+
   return true;
 }
 
@@ -2412,43 +2414,61 @@ void ShelfLayoutManager::SendA11yAlertForFullscreenWorkspaceState(
   previous_workspace_window_state_ = current_workspace_window_state;
 }
 
-void ShelfLayoutManager::MaybeStartDragWindowFromShelf(
+bool ShelfLayoutManager::MaybeStartDragWindowFromShelf(
     const ui::LocatedEvent& event_in_screen) {
   if (!features::IsDragFromShelfToHomeOrOverviewEnabled())
-    return;
+    return false;
   if (!IsTabletModeEnabled())
-    return;
+    return false;
   if (drag_status_ != kDragInProgress)
-    return;
+    return false;
 
   // Do not drag on a auto-hide hidden shelf or a hidden shelf.
   if ((visibility_state() == SHELF_AUTO_HIDE &&
        auto_hide_state() == SHELF_AUTO_HIDE_HIDDEN) ||
       visibility_state() == SHELF_HIDDEN) {
-    return;
+    return false;
   }
 
-  // If the start location is above the shelf (e.g., on the extended hotseat),
-  // do not allow the drag.
-  const gfx::Rect shelf_bounds = GetVisibleShelfBounds();
-  if (event_in_screen.location().y() < shelf_bounds.y())
-    return;
+  // Do not drag on kShown hotseat (it should be in home screen).
+  if (hotseat_state() == HotseatState::kShown)
+    return false;
+
+  // If hotseat is hidden when drag starts, do not start drag window if hotseat
+  // hasn't been fully dragged up.
+  if (hotseat_state() == HotseatState::kHidden) {
+    ShelfConfig* shelf_config = ShelfConfig::Get();
+    const int full_drag_amount =
+        -(shelf_config->shelf_size() + shelf_config->hotseat_bottom_padding() +
+          shelf_config->hotseat_size());
+    if (drag_amount_ > full_drag_amount)
+      return false;
+  } else if (hotseat_state() == HotseatState::kExtended) {
+    // If the start location is above the shelf (e.g., on the extended hotseat),
+    // do not allow the drag.
+    const gfx::Rect shelf_bounds = GetVisibleShelfBounds();
+    if (event_in_screen.location().y() < shelf_bounds.y())
+      return false;
+  }
 
   aura::Window* window =
       GetWindowForDragToHomeOrOverview(event_in_screen.location());
   if (!window)
-    return;
+    return false;
 
   window_drag_controller_ =
       std::make_unique<DragWindowFromShelfController>(window);
+  return true;
 }
 
 void ShelfLayoutManager::MaybeUpdateWindowDrag(
     const ui::LocatedEvent& event_in_screen,
     float scroll_x,
     float scroll_y) {
-  if (!window_drag_controller_)
+  if (!window_drag_controller_ &&
+      !MaybeStartDragWindowFromShelf(event_in_screen)) {
     return;
+  }
 
   DCHECK_EQ(drag_status_, kDragInProgress);
   window_drag_controller_->Drag(event_in_screen.location(), scroll_x, scroll_y);

ash/shelf/shelf_layout_manager.h

@@ -508,7 +508,7 @@ class ASH_EXPORT ShelfLayoutManager : public AppListControllerObserver,
       WorkspaceWindowState current_workspace_window_state);
 
   // Maybe start/update/end the window drag when swiping up from the shelf.
-  void MaybeStartDragWindowFromShelf(const ui::LocatedEvent& event_in_screen);
+  bool MaybeStartDragWindowFromShelf(const ui::LocatedEvent& event_in_screen);
   void MaybeUpdateWindowDrag(const ui::LocatedEvent& event_in_screen,
                              float scroll_x,
                              float scroll_y);

ash/shelf/shelf_layout_manager_unittest.cc

@@ -4046,14 +4046,16 @@ class ShelfLayoutManagerWindowDraggingTest : public ShelfLayoutManagerTestBase {
 TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
   const gfx::Rect shelf_widget_bounds =
       GetShelfWidget()->GetWindowBoundsInScreen();
+  const int shelf_size = ShelfConfig::Get()->shelf_size();
   const int hotseat_size = ShelfConfig::Get()->hotseat_size();
+  const int hotseat_padding_size = ShelfConfig::Get()->hotseat_bottom_padding();
 
   // Starts the drag from the center of the shelf's bottom.
   gfx::Point start = shelf_widget_bounds.bottom_center();
   StartScroll(start);
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   // We need at least one window to work with.
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
-  UpdateScroll(-shelf_widget_bounds.height() - hotseat_size);
   EndScroll(/*is_fling=*/false, 0.f);
 
   std::unique_ptr<aura::Window> window =
@@ -4061,6 +4063,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
   wm::ActivateWindow(window.get());
 
   StartScroll(start);
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   DragWindowFromShelfController* window_drag_controller =
       GetShelfLayoutManager()->window_drag_controller_for_testing();
   EXPECT_TRUE(window_drag_controller);
@@ -4072,8 +4075,8 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
   // The window needs to be visible to drag up.
   window->Hide();
   StartScroll(start);
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
-  UpdateScroll(-shelf_widget_bounds.height() - hotseat_size);
   EndScroll(/*is_fling=*/false, 0.f);
 
   // In splitview, depends on the drag position, the active dragged window might
@@ -4085,6 +4088,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
   split_view_controller->SnapWindow(window.get(), SplitViewController::LEFT);
   split_view_controller->SnapWindow(window2.get(), SplitViewController::RIGHT);
   StartScroll(shelf_widget_bounds.bottom_left());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   window_drag_controller =
       GetShelfLayoutManager()->window_drag_controller_for_testing();
   EXPECT_TRUE(window_drag_controller);
@@ -4093,6 +4097,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
 
   StartScroll(shelf_widget_bounds.bottom_right());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   window_drag_controller =
       GetShelfLayoutManager()->window_drag_controller_for_testing();
   EXPECT_TRUE(window_drag_controller);
@@ -4106,6 +4111,9 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, DraggedMRUWindow) {
 TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpInOverview) {
   const gfx::Rect shelf_widget_bounds =
       GetShelfWidget()->GetWindowBoundsInScreen();
+  const int shelf_size = ShelfConfig::Get()->shelf_size();
+  const int hotseat_size = ShelfConfig::Get()->hotseat_size();
+  const int hotseat_padding_size = ShelfConfig::Get()->hotseat_bottom_padding();
   std::unique_ptr<aura::Window> window1 =
       AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400));
   std::unique_ptr<aura::Window> window2 =
@@ -4117,6 +4125,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpInOverview) {
   overview_controller->StartOverview();
   gfx::Point start = shelf_widget_bounds.bottom_center();
   StartScroll(start);
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 
@@ -4130,6 +4139,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpInOverview) {
   EXPECT_TRUE(split_view_controller->InSplitViewMode());
   EXPECT_TRUE(overview_controller->InOverviewSession());
   StartScroll(shelf_widget_bounds.bottom_right());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 }
@@ -4141,11 +4151,16 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpForHiddenShelf) {
       AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400));
   wm::ActivateWindow(window.get());
   Shelf* shelf = GetPrimaryShelf();
+  const int shelf_size = ShelfConfig::Get()->shelf_size();
+  const int hotseat_size = ShelfConfig::Get()->hotseat_size();
+  const int hotseat_padding_size = ShelfConfig::Get()->hotseat_bottom_padding();
+
   // The window can be dragged on a visible shelf.
   const gfx::Rect shelf_widget_bounds =
       GetShelfWidget()->GetWindowBoundsInScreen();
   EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
   StartScroll(shelf_widget_bounds.bottom_center());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_TRUE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 
@@ -4159,6 +4174,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpForHiddenShelf) {
   gfx::Rect display_bounds =
       display::Screen::GetScreen()->GetPrimaryDisplay().bounds();
   StartScroll(display_bounds.bottom_center());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 
@@ -4166,6 +4182,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpForHiddenShelf) {
   SwipeUpOnShelf();
   EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->GetAutoHideState());
   StartScroll(display_bounds.bottom_center());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_TRUE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 
@@ -4173,6 +4190,7 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpForHiddenShelf) {
   SetState(GetShelfLayoutManager(), SHELF_HIDDEN);
   EXPECT_EQ(SHELF_HIDDEN, shelf->GetVisibilityState());
   StartScroll(display_bounds.bottom_center());
+  UpdateScroll(-shelf_size - hotseat_size - hotseat_padding_size);
   EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
   EndScroll(/*is_fling=*/false, 0.f);
 }
@@ -4195,6 +4213,33 @@ TEST_F(ShelfLayoutManagerWindowDraggingTest, NoOpIfDragStartsAboveShelf) {
   EndScroll(/*is_fling=*/false, 0.f);
 }
 
+// Tests that the MRU window can only be dragged window after the hotseat is
+// fully dragged up if hotseat was hidden before.
+TEST_F(ShelfLayoutManagerWindowDraggingTest, StartsDragAfterHotseatIsUp) {
+  std::unique_ptr<aura::Window> window =
+      AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400));
+  wm::ActivateWindow(window.get());
+
+  const gfx::Rect shelf_widget_bounds =
+      GetShelfWidget()->GetWindowBoundsInScreen();
+  const int shelf_size = ShelfConfig::Get()->shelf_size();
+  const int hotseat_size = ShelfConfig::Get()->hotseat_size();
+  const int hotseat_padding_size = ShelfConfig::Get()->hotseat_bottom_padding();
+
+  // Starts the drag from the center of the shelf's bottom.
+  gfx::Point start = shelf_widget_bounds.bottom_center();
+  StartScroll(start);
+  EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
+  // Continues the drag until the hotseat should have been fully dragged up.
+  UpdateScroll(-shelf_size);
+  EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
+  UpdateScroll(-hotseat_padding_size);
+  EXPECT_FALSE(GetShelfLayoutManager()->window_drag_controller_for_testing());
+  UpdateScroll(-hotseat_size);
+  EXPECT_TRUE(GetShelfLayoutManager()->window_drag_controller_for_testing());
+  EndScroll(/*is_fling=*/false, 0.f);
+}
+
 class ShelfLayoutManagerKeyboardTest : public AshTestBase {
  public:
   ShelfLayoutManagerKeyboardTest() = default;