overview gesture: Swipe up from shelf to drag the active window around.

See https://docs.google.com/document/d/1rskVuhK9wAqgntcq9WYPSknMEc_jsAp3zrqb4YSMAqE/edit#
for the mock and expected behaviors.

See crbug.com/997885#c5 for demo. For now with this CL in place, we can
only drag the window around. More will be done in follow up Cls.

Bug: 997885
Change-Id: Iecea3a8cb4a6fe3c6a64ddddea08bc010cfb72dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1817105
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700306}

ash/home_screen/home_launcher_gesture_handler.h

@@ -6,6 +6,7 @@
 #define ASH_HOME_SCREEN_HOME_LAUNCHER_GESTURE_HANDLER_H_
 
 #include <map>
+#include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
@@ -42,6 +43,11 @@ class ASH_EXPORT HomeLauncherGestureHandler
     // Sliding up the MRU window to display launcher. If in overview mode,
     // slides up overview mode as well.
     kSlideUpToShow,
+    // Sliding up from the shelf to drag the MRU window (or one of the snapped
+    // window in splitview) around to enter either home launcher screen or to
+    // overview screen. If in overview mode, this mode is a no-op. Note: This
+    // mode is behind the feature flag kDragFromShelfToHomeOrOverview.
+    kDragWindowToHomeOrOverview,
     // Sliding down the MRU window to hide launcher.
     kSlideDownToHide,
   };
@@ -95,6 +101,8 @@ class ASH_EXPORT HomeLauncherGestureHandler
 
  private:
   class ScopedWindowModifier;
+  class DragWindowFromShelfController;
+
   FRIEND_TEST_ALL_PREFIXES(HomeLauncherModeGestureHandlerTest,
                            AnimatingToEndResetsState);
 
@@ -119,8 +127,9 @@ class ASH_EXPORT HomeLauncherGestureHandler
   // on the values in |window_values_| and |transient_descendants_values_|.
   // |progress| is between 0.0 and 1.0, where 0.0 means the window will have its
   // original opacity and transform, and 1.0 means the window will be faded out
-  // and transformed offscreen.
-  void UpdateWindows(double progress, bool animate);
+  // and transformed offscreen. This function is used by kSlideUpToShow and
+  // kSlideDownToHide mode.
+  void UpdateWindowsForSlideUpOrDown(double progress, bool animate);
 
   // Stop observing all windows and remove their local pointers.
   void RemoveObserversAndStopTracking();
@@ -137,9 +146,19 @@ class ASH_EXPORT HomeLauncherGestureHandler
 
   // Sets up windows that will be used in dragging and animation. If |window| is
   // not null for kSlideDownToHide mode, it will be set as the window to run
-  // slide down animation. |window| is not used for kSlideUpToShow mode. Returns
-  // true if windows are successfully set up.
-  bool SetUpWindows(Mode mode, aura::Window* window);
+  // slide down animation. |window| is not used for kSlideUpToShow or
+  // kDragWindowToHomeOrOverview mode. |location_in_screen| is only used for
+  // kDragWindowToHomeOrOverview mode to find the eligible widnow to drag.
+  // Returns true if windows are successfully set up.
+  bool SetUpWindows(Mode mode,
+                    aura::Window* window,
+                    base::Optional<gfx::Point> location_in_screen);
+
+  // Called by OnPress/Scroll/ReleaseEvent() when the drag from the shelf or
+  // from the top starts/continues/ends. |location| is in screen coordinate.
+  void OnDragStarted(const gfx::Point& location);
+  void OnDragContinued(const gfx::Point& location);
+  bool OnDragEnded(const gfx::Point& location);
 
   Mode mode_ = Mode::kNone;
 
@@ -187,6 +206,10 @@ class ASH_EXPORT HomeLauncherGestureHandler
   // The display where the windows are being processed.
   display::Display display_;
 
+  // The window drag controller that will be used in kDragWindowToHomeOrOverview
+  // mode. Will not be created in other modes.
+  std::unique_ptr<DragWindowFromShelfController> window_drag_controller_;
+
   base::ObserverList<HomeLauncherGestureHandlerObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(HomeLauncherGestureHandler);

ash/home_screen/home_launcher_gesture_handler_unittest.cc

@@ -426,6 +426,117 @@ TEST_F(HomeLauncherGestureHandlerTest, TransparentShelfWileDragging) {
                 ->GetShelfBackgroundType());
 }
 
+// Tests that in kDragWindowToHomeOrOverview mode, the dragged active window
+// might be different in different scenarios.
+TEST_F(HomeLauncherGestureHandlerTest, DraggedActiveWindow) {
+  const gfx::Rect shelf_bounds =
+      Shelf::ForWindow(Shell::GetPrimaryRootWindow())->GetIdealBounds();
+
+  // We need at least one window to work with.
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.CenterPoint());
+  EXPECT_FALSE(GetGestureHandler()->GetActiveWindow());
+
+  auto window1 = CreateWindowForTesting();
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.CenterPoint());
+  EXPECT_EQ(GetGestureHandler()->GetActiveWindow(), window1.get());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.CenterPoint());
+  EXPECT_FALSE(GetGestureHandler()->GetActiveWindow());
+
+  // Test in splitview, depends on the drag position, the active dragged window
+  // might be different.
+  auto window2 = CreateWindowForTesting();
+  SplitViewController* split_view_controller =
+      Shell::Get()->split_view_controller();
+  split_view_controller->SnapWindow(window1.get(), SplitViewController::LEFT);
+  split_view_controller->SnapWindow(window2.get(), SplitViewController::RIGHT);
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.bottom_left());
+  EXPECT_EQ(GetGestureHandler()->GetActiveWindow(), window1.get());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.bottom_left());
+  EXPECT_FALSE(GetGestureHandler()->GetActiveWindow());
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.bottom_right());
+  EXPECT_EQ(GetGestureHandler()->GetActiveWindow(), window2.get());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.bottom_right());
+  EXPECT_FALSE(GetGestureHandler()->GetActiveWindow());
+  split_view_controller->EndSplitView();
+
+  // In overview, drag from shelf is a no-op.
+  Shell::Get()->overview_controller()->StartOverview();
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.CenterPoint());
+  EXPECT_FALSE(GetGestureHandler()->GetActiveWindow());
+}
+
+// Tests that in kDragWindowToHomeOrOverview mode, we may hide different sets
+// of windows in different scenarios.
+TEST_F(HomeLauncherGestureHandlerTest, HideWindowDuringWindowDragging) {
+  const gfx::Rect shelf_bounds =
+      Shelf::ForWindow(Shell::GetPrimaryRootWindow())->GetIdealBounds();
+
+  auto window3 = CreateWindowForTesting();
+  auto window2 = CreateWindowForTesting();
+  auto window1 = CreateWindowForTesting();
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_TRUE(window3->IsVisible());
+
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.CenterPoint());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_FALSE(window2->IsVisible());
+  EXPECT_FALSE(window3->IsVisible());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.CenterPoint());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_TRUE(window3->IsVisible());
+
+  // In splitview mode, the snapped windows will stay visible during dragging.
+  SplitViewController* split_view_controller =
+      Shell::Get()->split_view_controller();
+  split_view_controller->SnapWindow(window1.get(), SplitViewController::LEFT);
+  split_view_controller->SnapWindow(window2.get(), SplitViewController::RIGHT);
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.bottom_left());
+  EXPECT_EQ(GetGestureHandler()->GetActiveWindow(), window1.get());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_FALSE(window3->IsVisible());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.bottom_left());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_TRUE(window3->IsVisible());
+
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.bottom_right());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_FALSE(window3->IsVisible());
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.bottom_right());
+  EXPECT_TRUE(window1->IsVisible());
+  EXPECT_TRUE(window2->IsVisible());
+  EXPECT_TRUE(window3->IsVisible());
+}
+
+TEST_F(HomeLauncherGestureHandlerTest, HideHomeLauncherDuringDraggingTest) {
+  UpdateDisplay("400x400");
+  const gfx::Rect shelf_bounds =
+      Shelf::ForWindow(Shell::GetPrimaryRootWindow())->GetIdealBounds();
+  auto window = CreateWindowForTesting();
+  GetGestureHandler()->OnPressEvent(Mode::kDragWindowToHomeOrOverview,
+                                    shelf_bounds.CenterPoint());
+  GetGestureHandler()->OnScrollEvent(gfx::Point(0, 300), 1.f);
+  aura::Window* home_screen_window =
+      Shell::Get()->home_screen_controller()->delegate()->GetHomeScreenWindow();
+  EXPECT_TRUE(home_screen_window);
+  EXPECT_FALSE(home_screen_window->IsVisible());
+
+  GetGestureHandler()->OnReleaseEvent(shelf_bounds.CenterPoint());
+  EXPECT_TRUE(home_screen_window->IsVisible());
+}
+
 class HomeLauncherModeGestureHandlerTest
     : public HomeLauncherGestureHandlerTest,
       public testing::WithParamInterface<Mode> {

ash/public/cpp/ash_features.cc

@@ -96,6 +96,9 @@ const base::Feature kEnableBackgroundBlur{"EnableBackgroundBlur",
 const base::Feature kSwipingFromLeftEdgeToGoBack{
     "SwipingFromLeftEdgeToGoBack", base::FEATURE_DISABLED_BY_DEFAULT};
 
+const base::Feature kDragFromShelfToHomeOrOverview{
+    "DragFromShelfToHomeOrOverview", base::FEATURE_DISABLED_BY_DEFAULT};
+
 bool IsHideArcMediaNotificationsEnabled() {
   return base::FeatureList::IsEnabled(kMediaSessionNotification) &&
          base::FeatureList::IsEnabled(kHideArcMediaNotifications);
@@ -181,5 +184,9 @@ bool IsSwipingFromLeftEdgeToGoBackEnabled() {
   return base::FeatureList::IsEnabled(kSwipingFromLeftEdgeToGoBack);
 }
 
+bool IsDragFromShelfToHomeOrOverviewEnabled() {
+  return base::FeatureList::IsEnabled(kDragFromShelfToHomeOrOverview);
+}
+
 }  // namespace features
 }  // namespace ash

ash/public/cpp/ash_features.h

@@ -125,6 +125,12 @@ ASH_PUBLIC_EXPORT extern const base::Feature kUnifiedMessageCenterRefactor;
 // display. Only for tablet mode.
 ASH_PUBLIC_EXPORT extern const base::Feature kSwipingFromLeftEdgeToGoBack;
 
+// Enables dragging from shelf to enter home screen or overview feature.
+// Only for tablet mode.
+// TODO(https://crbug.com/992642): Remove this after this feature is fully
+// launched.
+ASH_PUBLIC_EXPORT extern const base::Feature kDragFromShelfToHomeOrOverview;
+
 ASH_PUBLIC_EXPORT bool IsHideArcMediaNotificationsEnabled();
 
 ASH_PUBLIC_EXPORT bool IsKeyboardShortcutViewerAppEnabled();
@@ -165,6 +171,8 @@ ASH_PUBLIC_EXPORT bool IsBackgroundBlurEnabled();
 
 ASH_PUBLIC_EXPORT bool IsSwipingFromLeftEdgeToGoBackEnabled();
 
+ASH_PUBLIC_EXPORT bool IsDragFromShelfToHomeOrOverviewEnabled();
+
 }  // namespace features
 }  // namespace ash
 

ash/shelf/shelf_layout_manager.cc

@@ -166,7 +166,7 @@ class HideAnimationObserver : public ui::ImplicitAnimationObserver {
 class HotseatEventHandler : public ui::EventHandler,
                             public ShelfLayoutManagerObserver {
  public:
-  HotseatEventHandler(ShelfLayoutManager* shelf_layout_manager)
+  explicit HotseatEventHandler(ShelfLayoutManager* shelf_layout_manager)
       : shelf_layout_manager_(shelf_layout_manager) {
     shelf_layout_manager_->AddObserver(this);
     Shell::Get()->AddPreTargetHandler(this);
@@ -1829,9 +1829,12 @@ bool ShelfLayoutManager::StartGestureDrag(
     drag_status_ = kDragAppListInProgress;
     HomeLauncherGestureHandler* home_launcher_handler =
         Shell::Get()->home_screen_controller()->home_launcher_gesture_handler();
-    if (home_launcher_handler->OnPressEvent(
-            HomeLauncherGestureHandler::Mode::kSlideUpToShow,
-            gesture_in_screen.location())) {
+    HomeLauncherGestureHandler::Mode slide_mode =
+        features::IsDragFromShelfToHomeOrOverviewEnabled()
+            ? HomeLauncherGestureHandler::Mode::kDragWindowToHomeOrOverview
+            : HomeLauncherGestureHandler::Mode::kSlideUpToShow;
+    if (home_launcher_handler->OnPressEvent(slide_mode,
+                                            gesture_in_screen.location())) {
       return true;
     }
     drag_status_ = previous_drag_status;
@@ -1889,7 +1892,7 @@ void ShelfLayoutManager::UpdateMouseDrag(
   if (drag_status_ == kDragAttempt) {
     // Do not start drag for the small offset.
     if (abs(mouse_in_screen.location().y() - last_mouse_drag_position_.y()) <
-      kMouseDragThreshold) {
+        kMouseDragThreshold) {
       return;
     }