overview: Renable dragging windows on overview title bars.

Change of mind. Mostly a revert of
https://chromium-review.googlesource.com/c/chromium/src/+/911849.

Test: ash_unittests WindowSelectorTest.*
Bug: 825637
Change-Id: I37bead0a8b1d80cd0c89c646feb5af2a1f0ffa1a
Reviewed-on: https://chromium-review.googlesource.com/986942Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546978}

ash/wm/overview/window_selector_item.cc

@@ -256,7 +256,7 @@ class ShieldButton : public views::Button {
           listener()->HandleReleaseEvent(location);
           break;
         case ui::ET_GESTURE_TAP:
-          listener()->ActivateDraggedWindow(location);
+          listener()->ActivateDraggedWindow();
           break;
         case ui::ET_GESTURE_END:
           listener()->ResetDraggedWindowGesture();
@@ -963,54 +963,27 @@ float WindowSelectorItem::GetItemScale(const gfx::Size& size) {
 
 void WindowSelectorItem::HandlePressEvent(
     const gfx::Point& location_in_screen) {
-  // Check the y position instead of using GetBoundsInScreen().Contains() so
-  // that it includes the image, close button and invisible margins.
-  tap_down_event_on_title_ = base::nullopt;
-  if (IsNewOverviewUi() &&
-      location_in_screen.y() < background_view_->GetBoundsInScreen().bottom()) {
-    tap_down_event_on_title_ = base::make_optional(location_in_screen);
-    return;
-  }
-
   StartDrag();
   window_selector_->InitiateDrag(this, location_in_screen);
 }
 
 void WindowSelectorItem::HandleReleaseEvent(
     const gfx::Point& location_in_screen) {
-  if (tap_down_event_on_title_) {
-    SelectWindowIfBelowDistanceThreshold(location_in_screen);
-    return;
-  }
-
   EndDrag();
   window_selector_->CompleteDrag(this, location_in_screen);
 }
 
 void WindowSelectorItem::HandleDragEvent(const gfx::Point& location_in_screen) {
-  if (tap_down_event_on_title_)
-    return;
-
   window_selector_->Drag(this, location_in_screen);
 }
 
-void WindowSelectorItem::ActivateDraggedWindow(
-    const gfx::Point& location_in_screen) {
-  if (tap_down_event_on_title_) {
-    SelectWindowIfBelowDistanceThreshold(location_in_screen);
-    return;
-  }
-
+void WindowSelectorItem::ActivateDraggedWindow() {
   DCHECK_EQ(this, window_selector_->window_drag_controller()->item());
   window_selector_->ActivateDraggedWindow();
 }
 
 void WindowSelectorItem::ResetDraggedWindowGesture() {
   OnSelectorItemDragEnded();
-
-  if (tap_down_event_on_title_)
-    return;
-
   DCHECK_EQ(this, window_selector_->window_drag_controller()->item());
   window_selector_->ResetDraggedWindowGesture();
 }
@@ -1329,16 +1302,6 @@ void WindowSelectorItem::FadeOut(std::unique_ptr<views::Widget> widget) {
   widget_ptr->SetOpacity(0.f);
 }
 
-void WindowSelectorItem::SelectWindowIfBelowDistanceThreshold(
-    const gfx::Point& event_location) {
-  DCHECK(tap_down_event_on_title_.has_value());
-
-  const gfx::Vector2d distance =
-      event_location - tap_down_event_on_title_.value();
-  if (distance.Length() < OverviewWindowDragController::kMinimumDragOffset)
-    window_selector_->SelectWindow(this);
-}
-
 gfx::SlideAnimation* WindowSelectorItem::GetBackgroundViewAnimation() {
   return background_view_ ? background_view_->animation() : nullptr;
 }

ash/wm/overview/window_selector_item.h

@@ -182,7 +182,7 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   void HandlePressEvent(const gfx::Point& location_in_screen);
   void HandleReleaseEvent(const gfx::Point& location_in_screen);
   void HandleDragEvent(const gfx::Point& location_in_screen);
-  void ActivateDraggedWindow(const gfx::Point& location_in_screen);
+  void ActivateDraggedWindow();
   void ResetDraggedWindowGesture();
 
   // Sets the bounds of the window shadow. If |bounds_in_screen| is nullopt,
@@ -308,11 +308,6 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   // when the item is selected.
   bool selected_;
 
-  // Has a value if last seen tap down event was on the title bar. Behavior of
-  // subsequent drags/tap up differ if the original event was on the overview
-  // title.
-  base::Optional<gfx::Point> tap_down_event_on_title_;
-
   // A widget that covers the |transform_window_|. The widget has
   // |caption_container_view_| as its contents view. The widget is backed by a
   // NOT_DRAWN layer since most of its surface is transparent.
@@ -373,8 +368,6 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   // rounded edges mask applied on entering overview window.
   std::unique_ptr<ui::Shadow> shadow_;
 
-  bool event_on_title_ = false;
-
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorItem);
 };
 

ash/wm/overview/window_selector_unittest.cc

@@ -4068,47 +4068,6 @@ TEST_F(SplitViewWindowSelectorTest,
   EXPECT_FALSE(wm::IsActiveWindow(window1.get()));
 }
 
-// Verify that events that originate on the overview title bar will not allow
-// the item to be dragged or enter splitview, but will still be able to select a
-// window.
-TEST_F(SplitViewWindowSelectorTest, EventsOnOverviewTitleBar) {
-  const gfx::Rect bounds(400, 400);
-  std::unique_ptr<aura::Window> window1(CreateWindow(bounds));
-
-  ToggleOverview();
-
-  const int grid_index = 0;
-  WindowSelectorItem* selector_item1 =
-      GetWindowItemForWindow(grid_index, window1.get());
-  const gfx::Rect original_bounds = selector_item1->target_bounds();
-
-  // Click on the title of the selector item.
-  const gfx::Point point_on_title =
-      GetLabelView(selector_item1)->GetBoundsInScreen().CenterPoint();
-  GetEventGenerator().MoveMouseTo(point_on_title);
-  GetEventGenerator().PressLeftButton();
-
-  // Verify that dragging the mouse does change the selector item bounds.
-  GetEventGenerator().MoveMouseTo(0, 0);
-  EXPECT_EQ(original_bounds, selector_item1->target_bounds());
-
-  // We dragged into the left snap region. Verify that after releasing the
-  // mouse, we do not enter split view mode, which would be the case if we did
-  // not click on the title.
-  GetEventGenerator().ReleaseLeftButton();
-  EXPECT_FALSE(split_view_controller()->IsSplitViewModeActive());
-
-  // Verify that clicking on the title still exits overview and activates the
-  // associated window of the clicked selector item.
-  ASSERT_TRUE(window_selector());
-  GetEventGenerator().MoveMouseTo(point_on_title);
-  GetEventGenerator().PressLeftButton();
-  GetEventGenerator().ReleaseLeftButton();
-
-  EXPECT_FALSE(window_selector());
-  EXPECT_TRUE(wm::IsActiveWindow(window1.get()));
-}
-
 // Test that when splitview mode is active, minimizing one of the snapped window
 // will insert the minimized window back to overview mode if overview mode is
 // active at the moment.