Items in AUTO_HIDE_SHOWN shelf should can be dragged after context menu is shown.

Changes in this cl:
- Make sure ShelfLayoutManager doesn't handle the following gesture events after
  ET_GESTURE_SCROLL_BEGIN for auto_hide shelf. Then they can still be propagated
  to ShelfButton to process the drag and drop.

- Start the gesture drag and ink drop timer of the shelf item only if the shelf
  is visible. Then gesture drag on the item in AUTO_HIDE_HIDDEN shelf will not
  activate the ink drop of the shelf item.

- Update the shelf visibility in ShelfView::OnMenuClosed only if there is no
  shelf item in drag. Since shelf should be kept as visible during drag even the
  menu is closed.

Bug: 905847
Change-Id: I384b4c4b3bc2d240820cea338c4ddc59d8cc517a
Reviewed-on: https://chromium-review.googlesource.com/c/1340952
Commit-Queue: Min Chen <minch@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609842}

ash/shelf/shelf.cc

@@ -95,6 +95,10 @@ void Shelf::DestroyShelfWidget() {
   shelf_widget_.reset();
 }
 
+bool Shelf::IsVisible() const {
+  return shelf_layout_manager_->IsVisible();
+}
+
 aura::Window* Shelf::GetWindow() {
   return shelf_widget_->GetNativeWindow();
 }

ash/shelf/shelf.h

@@ -59,6 +59,11 @@ class ASH_EXPORT Shelf : public ShelfLayoutManagerObserver {
     return shelf_layout_manager_;
   }
 
+  // Returns true if the shelf is visible. Shelf can be visible in 1)
+  // SHELF_VISIBLE or 2) SHELF_AUTO_HIDE but in SHELF_AUTO_HIDE_SHOWN. See
+  // details in ShelfLayoutManager::IsVisible.
+  bool IsVisible() const;
+
   ShelfWidget* shelf_widget() { return shelf_widget_.get(); }
 
   // Returns the window showing the shelf.

ash/shelf/shelf_button.cc

@@ -605,16 +605,20 @@ void ShelfButton::ChildPreferredSizeChanged(views::View* child) {
 void ShelfButton::OnGestureEvent(ui::GestureEvent* event) {
   switch (event->type()) {
     case ui::ET_GESTURE_TAP_DOWN:
-      AddState(STATE_HOVERED);
-      drag_timer_.Start(
-          FROM_HERE, base::TimeDelta::FromMilliseconds(kDragTimeThresholdMs),
-          base::Bind(&ShelfButton::OnTouchDragTimer, base::Unretained(this)));
-      ripple_activation_timer_.Start(
-          FROM_HERE,
-          base::TimeDelta::FromMilliseconds(kInkDropRippleActivationTimeMs),
-          base::Bind(&ShelfButton::OnRippleTimer, base::Unretained(this)));
-      GetInkDrop()->AnimateToState(views::InkDropState::ACTION_PENDING);
-      event->SetHandled();
+      if (shelf_view_->shelf()->IsVisible()) {
+        AddState(STATE_HOVERED);
+        drag_timer_.Start(
+            FROM_HERE, base::TimeDelta::FromMilliseconds(kDragTimeThresholdMs),
+            base::BindRepeating(&ShelfButton::OnTouchDragTimer,
+                                base::Unretained(this)));
+        ripple_activation_timer_.Start(
+            FROM_HERE,
+            base::TimeDelta::FromMilliseconds(kInkDropRippleActivationTimeMs),
+            base::BindRepeating(&ShelfButton::OnRippleTimer,
+                                base::Unretained(this)));
+        GetInkDrop()->AnimateToState(views::InkDropState::ACTION_PENDING);
+        event->SetHandled();
+      }
       break;
     case ui::ET_GESTURE_END:
       drag_timer_.Stop();

ash/shelf/shelf_layout_manager.cc

@@ -394,13 +394,6 @@ bool ShelfLayoutManager::ProcessGestureEvent(
 
   if (gesture_drag_status_ != GESTURE_DRAG_IN_PROGRESS &&
       gesture_drag_status_ != GESTURE_DRAG_APPLIST_IN_PROGRESS) {
-    if ((shelf_->GetVisibilityState() == SHELF_AUTO_HIDE &&
-         shelf_->GetAutoHideState() == SHELF_AUTO_HIDE_HIDDEN) ||
-        shelf_->GetVisibilityState() == SHELF_HIDDEN) {
-      // Do not allow children to handle events while the shelf is hidden.
-      return true;
-    }
-
     return false;
   }
 

ash/shelf/shelf_view.cc

@@ -2130,8 +2130,12 @@ void ShelfView::OnMenuClosed(views::View* source) {
 
   shelf_menu_model_adapter_.reset();
 
-  // Auto-hide or alignment might have changed, but only for this shelf.
-  shelf_->UpdateVisibilityState();
+  const bool is_in_drag = item && ShelfButtonIsInDrag(item->type, source);
+  // Update the shelf visibility since auto-hide or alignment might have
+  // changes, but don't update if shelf item is being dragged. Since shelf
+  // should be kept as visible during shelf item drag even menu is closed.
+  if (!is_in_drag)
+    shelf_->UpdateVisibilityState();
 }
 
 void ShelfView::OnBoundsAnimatorProgressed(views::BoundsAnimator* animator) {

ash/shelf/shelf_view_unittest.cc

@@ -2085,6 +2085,64 @@ TEST_F(ShelfViewTest, ShelfDragViewAndContextMenu) {
   EXPECT_FALSE(shelf_view_->drag_view());
 }
 
+// Tests that shelf items in always shown shelf can be dragged through gesture
+// events after context menu is shown.
+TEST_F(ShelfViewTest, DragAppAfterContextMenuIsShownInAlwaysShownShelf) {
+  ASSERT_EQ(SHELF_VISIBLE, GetPrimaryShelf()->GetVisibilityState());
+  ui::test::EventGenerator* generator = GetEventGenerator();
+  const ShelfID first_app_id = AddAppShortcut();
+  const ShelfID second_app_id = AddAppShortcut();
+  const int last_index = model_->items().size() - 1;
+  ASSERT_TRUE(last_index >= 0);
+
+  const gfx::Point start = GetButtonCenter(first_app_id);
+  // Drag the app long enough to ensure the drag can be triggered.
+  const gfx::Point end(start.x() + 100, start.y());
+  generator->set_current_location(start);
+
+  // Add |STATE_DRAGGING| state to emulate the gesture drag after context menu
+  // is shown.
+  GetButtonByID(first_app_id)->AddState(ShelfButton::STATE_DRAGGING);
+  generator->GestureScrollSequence(start, end,
+                                   base::TimeDelta::FromMilliseconds(100), 3);
+
+  // |first_add_id| has been moved to the end of the items in the shelf.
+  EXPECT_EQ(first_app_id, model_->items()[last_index].id);
+}
+
+// Tests that shelf items in AUTO_HIDE_SHOWN shelf can be dragged through
+// gesture events after context menu is shown.
+TEST_F(ShelfViewTest, DragAppAfterContextMenuIsShownInAutoHideShelf) {
+  ui::test::EventGenerator* generator = GetEventGenerator();
+  const ShelfID first_app_id = AddAppShortcut();
+  const ShelfID second_app_id = AddAppShortcut();
+  const int last_index = model_->items().size() - 1;
+
+  Shelf* shelf = GetPrimaryShelf();
+  std::unique_ptr<views::Widget> widget = CreateTestWidget();
+  widget->Show();
+  shelf->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS);
+  EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
+  EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->GetAutoHideState());
+
+  shelf->shelf_widget()->GetFocusCycler()->RotateFocus(FocusCycler::FORWARD);
+  EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->GetAutoHideState());
+
+  const gfx::Point start = GetButtonCenter(first_app_id);
+  // Drag the app long enough to ensure the drag can be triggered.
+  const gfx::Point end = gfx::Point(start.x() + 100, start.y());
+  generator->set_current_location(start);
+
+  // Add |STATE_DRAGGING| state to emulate the gesture drag after context menu
+  // is shown.
+  GetButtonByID(first_app_id)->AddState(ShelfButton::STATE_DRAGGING);
+  generator->GestureScrollSequence(start, end,
+                                   base::TimeDelta::FromMilliseconds(100), 3);
+
+  // |first_add_id| has been moved to the end of the items in the shelf.
+  EXPECT_EQ(first_app_id, model_->items()[last_index].id);
+}
+
 struct TouchableAppContextMenuTestParams {
   TouchableAppContextMenuTestParams(bool enable_touchable_app_context_menu,
                                     bool context_menu)