Virtual Desks: Suppress DesksBar in tablet mode when there's only one desk

This effectively disables the feature in tablet mode if entered before
creating more than one desk.

BUG=976442
TEST=Manual, added a new test.

Change-Id: I38966dd59cf0eb76873958ca0fb4472c9bf5a53f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1666548
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670347}

ash/wm/desks/desks_unittests.cc

@@ -1213,6 +1213,48 @@ TEST_F(DesksTest, TabletModeBackdrops) {
   EXPECT_FALSE(desk_2_backdrop_controller->backdrop_window());
 }
 
+TEST_F(DesksTest, NoDesksBarInTabletModeWithOneDesk) {
+  // Initially there's only one desk.
+  auto* controller = DesksController::Get();
+  ASSERT_EQ(1u, controller->desks().size());
+
+  auto window = CreateTestWindow(gfx::Rect(0, 0, 250, 100));
+  wm::ActivateWindow(window.get());
+  EXPECT_EQ(window.get(), wm::GetActiveWindow());
+
+  // Enter tablet mode and expect that the DesksBar widget won't be created.
+  // Avoid TabletModeController::OnGetSwitchStates() from disabling tablet mode.
+  base::RunLoop().RunUntilIdle();
+  Shell::Get()->tablet_mode_controller()->SetEnabledForTest(true);
+
+  auto* overview_controller = Shell::Get()->overview_controller();
+  overview_controller->StartOverview();
+  EXPECT_TRUE(overview_controller->InOverviewSession());
+  const auto* overview_grid =
+      GetOverviewGridForRoot(Shell::GetPrimaryRootWindow());
+  const auto* desks_bar_view = overview_grid->GetDesksBarViewForTesting();
+  ASSERT_FALSE(desks_bar_view);
+
+  // It's possible to drag the window without any crashes.
+  auto* overview_session = overview_controller->overview_session();
+  auto* overview_item =
+      overview_session->GetOverviewItemForWindow(window.get());
+  DragItemToPoint(overview_item, window->GetBoundsInScreen().CenterPoint(),
+                  GetEventGenerator(), /*drop=*/true);
+
+  // Exit overview and add a new desk, then re-enter overview. Expect that now
+  // the desks bar is visible.
+  overview_controller->EndOverview();
+  EXPECT_FALSE(overview_controller->InOverviewSession());
+  controller->NewDesk();
+  overview_controller->StartOverview();
+  EXPECT_TRUE(overview_controller->InOverviewSession());
+  overview_grid = GetOverviewGridForRoot(Shell::GetPrimaryRootWindow());
+  desks_bar_view = overview_grid->GetDesksBarViewForTesting();
+  ASSERT_TRUE(desks_bar_view);
+  ASSERT_EQ(2u, desks_bar_view->mini_views().size());
+}
+
 TEST_F(DesksTest, TabletModeDesksCreationRemovalCycle) {
   auto window = CreateTestWindow(gfx::Rect(0, 0, 250, 100));
   wm::ActivateWindow(window.get());

ash/wm/desks/desks_util.cc

@@ -6,6 +6,7 @@
 
 #include "ash/public/cpp/ash_features.h"
 #include "ash/public/cpp/shell_window_ids.h"
+#include "ash/public/cpp/tablet_mode.h"
 #include "ash/wm/desks/desk.h"
 #include "ash/wm/desks/desks_controller.h"
 #include "ui/aura/window.h"
@@ -122,6 +123,12 @@ aura::Window* GetDeskContainerForContext(aura::Window* context) {
   return nullptr;
 }
 
+bool ShouldDesksBarBeCreated() {
+  return features::IsVirtualDesksEnabled() &&
+         (!TabletMode::Get()->IsEnabled() ||
+          DesksController::Get()->desks().size() > 1);
+}
+
 }  // namespace desks_util
 
 }  // namespace ash

ash/wm/desks/desks_util.h

@@ -42,6 +42,9 @@ ASH_EXPORT bool BelongsToActiveDesk(aura::Window* window);
 // container, otherwise return nullptr.
 ASH_EXPORT aura::Window* GetDeskContainerForContext(aura::Window* context);
 
+// Returns true if the DesksBar widget should be created in overview mode.
+ASH_EXPORT bool ShouldDesksBarBeCreated();
+
 }  // namespace desks_util
 
 }  // namespace ash

ash/wm/overview/overview_grid.cc

@@ -24,6 +24,7 @@
 #include "ash/shell.h"
 #include "ash/wm/desks/desk_mini_view.h"
 #include "ash/wm/desks/desks_bar_view.h"
+#include "ash/wm/desks/desks_util.h"
 #include "ash/wm/overview/cleanup_animation_observer.h"
 #include "ash/wm/overview/drop_target_view.h"
 #include "ash/wm/overview/overview_constants.h"
@@ -1319,7 +1320,7 @@ aura::Window* OverviewGrid::GetTargetWindowOnLocation(
 }
 
 bool OverviewGrid::IsDesksBarViewActive() const {
-  DCHECK(features::IsVirtualDesksEnabled());
+  DCHECK(desks_util::ShouldDesksBarBeCreated());
 
   // The desk bar view is not active if there is only a single desk when
   // overview is started. Once there are more than one desk, it should stay
@@ -1329,7 +1330,7 @@ bool OverviewGrid::IsDesksBarViewActive() const {
 }
 
 gfx::Rect OverviewGrid::GetGridEffectiveBounds() const {
-  if (!features::IsVirtualDesksEnabled() || !IsDesksBarViewActive())
+  if (!desks_util::ShouldDesksBarBeCreated() || !IsDesksBarViewActive())
     return bounds_;
 
   gfx::Rect effective_bounds = bounds_;
@@ -1339,7 +1340,7 @@ gfx::Rect OverviewGrid::GetGridEffectiveBounds() const {
 
 bool OverviewGrid::UpdateDesksBarDragDetails(
     const gfx::Point& screen_location) {
-  DCHECK(features::IsVirtualDesksEnabled());
+  DCHECK(desks_util::ShouldDesksBarBeCreated());
 
   const bool dragged_item_over_bar =
       desks_widget_->GetWindowBoundsInScreen().Contains(screen_location);
@@ -1350,7 +1351,7 @@ bool OverviewGrid::UpdateDesksBarDragDetails(
 bool OverviewGrid::MaybeDropItemOnDeskMiniView(
     const gfx::Point& screen_location,
     OverviewItem* drag_item) {
-  DCHECK(features::IsVirtualDesksEnabled());
+  DCHECK(desks_util::ShouldDesksBarBeCreated());
 
   // End the drag for the DesksBarView.
   desks_bar_view_->SetDragDetails(screen_location,
@@ -1386,7 +1387,7 @@ bool OverviewGrid::MaybeDropItemOnDeskMiniView(
 }
 
 void OverviewGrid::MaybeInitDesksWidget() {
-  if (!features::IsVirtualDesksEnabled() || desks_widget_)
+  if (!desks_util::ShouldDesksBarBeCreated() || desks_widget_)
     return;
 
   desks_widget_ = DesksBarView::CreateDesksWidget(

ash/wm/overview/overview_item.cc

@@ -15,6 +15,7 @@
 #include "ash/scoped_animation_disabler.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
+#include "ash/wm/desks/desks_util.h"
 #include "ash/wm/drag_window_controller.h"
 #include "ash/wm/overview/delayed_animation_observer_impl.h"
 #include "ash/wm/overview/overview_animation_type.h"
@@ -764,7 +765,7 @@ void OverviewItem::UpdateMaskAndShadow() {
   OverviewController* overview_controller = Shell::Get()->overview_controller();
   if (disable_mask_ || !overview_controller ||
       !overview_controller->InOverviewSession() ||
-      (!ash::features::ShouldUseShaderRoundedCorner() &&
+      (!features::ShouldUseShaderRoundedCorner() &&
        overview_grid_->window_list().size() > 10) ||
       overview_controller->IsInStartAnimation() || is_being_dragged_ ||
       overview_grid_->IsDropTargetWindow(GetWindow()) ||
@@ -864,7 +865,7 @@ void OverviewItem::HandleDragEvent(const gfx::PointF& location_in_screen) {
 }
 
 void OverviewItem::HandleLongPressEvent(const gfx::PointF& location_in_screen) {
-  if (ShouldAllowSplitView() || features::IsVirtualDesksEnabled())
+  if (ShouldAllowSplitView() || desks_util::ShouldDesksBarBeCreated())
     overview_session_->StartNormalDragMode(location_in_screen);
 }
 

ash/wm/overview/overview_window_drag_controller.cc

@@ -12,6 +12,7 @@
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/wm/desks/desk_preview_view.h"
+#include "ash/wm/desks/desks_util.h"
 #include "ash/wm/overview/overview_constants.h"
 #include "ash/wm/overview/overview_controller.h"
 #include "ash/wm/overview/overview_grid.h"
@@ -95,7 +96,7 @@ OverviewWindowDragController::OverviewWindowDragController(
       item_(item),
       on_desks_bar_item_size_(GetItemSizeWhenOnDesksBar(item)),
       should_allow_split_view_(ShouldAllowSplitView()),
-      virtual_desks_enabled_(features::IsVirtualDesksEnabled()) {}
+      virtual_desks_bar_enabled_(desks_util::ShouldDesksBarBeCreated()) {}
 
 OverviewWindowDragController::~OverviewWindowDragController() = default;
 
@@ -132,7 +133,7 @@ void OverviewWindowDragController::Drag(const gfx::PointF& location_in_screen) {
       overview_session_->GetGridWithRootWindow(item_->root_window())
           ->StartNudge(item_);
       did_move_ = true;
-    } else if (should_allow_split_view_ || virtual_desks_enabled_) {
+    } else if (should_allow_split_view_ || virtual_desks_bar_enabled_) {
       StartNormalDragMode(location_in_screen);
     }
   }
@@ -183,7 +184,7 @@ OverviewWindowDragController::CompleteDrag(
 
 void OverviewWindowDragController::StartNormalDragMode(
     const gfx::PointF& location_in_screen) {
-  DCHECK(should_allow_split_view_ || virtual_desks_enabled_);
+  DCHECK(should_allow_split_view_ || virtual_desks_bar_enabled_);
 
   did_move_ = true;
   current_drag_behavior_ = DragBehavior::kNormalDrag;
@@ -334,7 +335,7 @@ gfx::RectF OverviewWindowDragController::ContinueNormalDrag(
   gfx::PointF centerpoint =
       location_in_screen - (initial_event_location_ - initial_centerpoint_);
 
-  if (virtual_desks_enabled_) {
+  if (virtual_desks_bar_enabled_) {
     if (item_->overview_grid()->UpdateDesksBarDragDetails(
             gfx::ToRoundedPoint(location_in_screen))) {
       // The drag location intersects the bounds of the DesksBarView, in this
@@ -391,7 +392,7 @@ OverviewWindowDragController::CompleteNormalDrag(
   }
 
   // Attempt to move a window to a different desk.
-  if (virtual_desks_enabled_) {
+  if (virtual_desks_bar_enabled_) {
     item_->SetOpacity(original_opacity_);
 
     if (item_->overview_grid()->MaybeDropItemOnDeskMiniView(

ash/wm/overview/overview_window_drag_controller.h

@@ -142,8 +142,8 @@ class ASH_EXPORT OverviewWindowDragController {
   // True if SplitView is enabled.
   const bool should_allow_split_view_;
 
-  // True if the Virtual Desks feature is enabled.
-  const bool virtual_desks_enabled_;
+  // True if the Virtual Desks bar is created and dragging to desks is enabled.
+  const bool virtual_desks_bar_enabled_;
 
   // False if the initial drag location was not a snap region, or if it was in
   // a snap region but the drag has since moved out.