overview: Avoid ending overview because of window activation change while an...

overview: Avoid ending overview because of window activation change while an overview item is being dragged

The present CL aims to address a problem similar to [1]. [2] addresses
[1] by modifying OverviewSession:OnWindowActivating() to avoid ending
overview while there exists a window in a dragged state. That solution
is fine for workflows where a window is dragged from the top in tablet
mode, but there is a similar problem (possibly introduced by [3], which
I have reverted but would like to reland) involving overview item
dragging, which is handled by OverviewWindowDragController and does not
put any window in a dragged state.

[1] https://crbug.com/955814
[2] https://chromium-review.googlesource.com/c/chromium/src/+/1626542
[3] https://chromium-review.googlesource.com/c/chromium/src/+/1627562

Bug: 961170, 967196
Change-Id: I059127b88b343ea56a995bd7b815d5f434877064
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1633109Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664370}

ash/wm/overview/overview_session.cc

@@ -143,19 +143,6 @@ gfx::Rect GetGridBoundsInScreen(aura::Window* root_window,
   return bounds;
 }
 
-bool IsWindowDragInProgress() {
-  auto windows = Shell::Get()->mru_window_tracker()->BuildMruWindowList();
-  for (auto* window : windows) {
-    wm::WindowState* window_state = wm::GetWindowState(window);
-    if (window_state && window_state->is_dragged() &&
-        (window_state->drag_details()->window_component == HTCLIENT ||
-         window_state->drag_details()->window_component == HTCAPTION)) {
-      return true;
-    }
-  }
-  return false;
-}
-
 }  // namespace
 
 OverviewSession::OverviewSession(OverviewDelegate* delegate)
@@ -716,9 +703,13 @@ void OverviewSession::OnWindowActivating(
   // Don't restore focus on exit if a window was just activated.
   ResetFocusRestoreWindow(false);
 
-  // Do not cancel overview mode if a window drag in progress.
-  if (IsWindowDragInProgress())
-    return;
+  // Do not cancel overview mode while a window or overview item is being
+  // dragged as evidenced by the presence of a drop target. (Dragging to close
+  // does not count; canceling overview mode is okay then.)
+  for (std::unique_ptr<OverviewGrid>& overview_grid : grid_list_) {
+    if (overview_grid->GetDropTarget())
+      return;
+  }
 
   const auto& windows = grid->window_list();
   auto iter = std::find_if(
@@ -1018,12 +1009,8 @@ void OverviewSession::OnDisplayBoundsChanged() {
 }
 
 void OverviewSession::MaybeCreateAndPositionNoWindowsWidget() {
-  // Hide the widget if there is an item in overview or there are none but there
-  // is a window drag in progress. It is possible for a window drag to be in
-  // progress when we notify that split view has started so check for that case.
-  if (!IsEmpty() ||
-      (IsWindowDragInProgress() &&
-       !Shell::Get()->split_view_controller()->InSplitViewMode())) {
+  // Hide the widget if there is an item in overview.
+  if (!IsEmpty()) {
     no_windows_widget_.reset();
     return;
   }

ash/wm/overview/overview_session_unittest.cc

@@ -1063,6 +1063,60 @@ TEST_F(OverviewSessionTest, ActivateAnotherWindowDuringDragNotCancelOverview) {
   EXPECT_TRUE(InOverviewSession());
 }
 
+// Tests that if an overview item is dragged, the activation of the
+// corresponding window does not cancel overview.
+TEST_F(OverviewSessionTest, ActivateDraggedOverviewWindowNotCancelOverview) {
+  UpdateDisplay("800x600");
+  EnterTabletMode();
+  std::unique_ptr<aura::Window> window(CreateTestWindow());
+  ToggleOverview();
+  OverviewItem* item = GetWindowItemForWindow(0, window.get());
+  gfx::PointF drag_point = item->target_bounds().CenterPoint();
+  overview_session()->InitiateDrag(item, drag_point);
+  drag_point.Offset(5.f, 0.f);
+  overview_session()->Drag(item, drag_point);
+  ::wm::ActivateWindow(window.get());
+  EXPECT_TRUE(InOverviewSession());
+}
+
+// Tests that if an overview item is dragged, the activation of the window
+// corresponding to another overview item does not cancel overview.
+TEST_F(OverviewSessionTest,
+       ActivateAnotherOverviewWindowDuringOverviewDragNotCancelOverview) {
+  UpdateDisplay("800x600");
+  EnterTabletMode();
+  std::unique_ptr<aura::Window> window1(CreateTestWindow());
+  std::unique_ptr<aura::Window> window2(CreateTestWindow());
+  ToggleOverview();
+  OverviewItem* item1 = GetWindowItemForWindow(0, window1.get());
+  gfx::PointF drag_point = item1->target_bounds().CenterPoint();
+  overview_session()->InitiateDrag(item1, drag_point);
+  drag_point.Offset(5.f, 0.f);
+  overview_session()->Drag(item1, drag_point);
+  ::wm::ActivateWindow(window2.get());
+  EXPECT_TRUE(InOverviewSession());
+}
+
+// Tests that if an overview item is dragged, the activation of a window
+// excluded from overview does not cancel overview.
+TEST_F(OverviewSessionTest,
+       ActivateWindowExcludedFromOverviewDuringOverviewDragNotCancelOverview) {
+  UpdateDisplay("800x600");
+  EnterTabletMode();
+  std::unique_ptr<aura::Window> window1(CreateTestWindow());
+  std::unique_ptr<aura::Window> window2(
+      CreateTestWindow(gfx::Rect(), aura::client::WINDOW_TYPE_POPUP));
+  EXPECT_TRUE(wm::ShouldExcludeForOverview(window2.get()));
+  ToggleOverview();
+  OverviewItem* item1 = GetWindowItemForWindow(0, window1.get());
+  gfx::PointF drag_point = item1->target_bounds().CenterPoint();
+  overview_session()->InitiateDrag(item1, drag_point);
+  drag_point.Offset(5.f, 0.f);
+  overview_session()->Drag(item1, drag_point);
+  ::wm::ActivateWindow(window2.get());
+  EXPECT_TRUE(InOverviewSession());
+}
+
 // Tests that exiting overview mode without selecting a window restores focus
 // to the previously focused window.
 TEST_F(OverviewSessionTest, CancelRestoresFocus) {