desks: Disable removing a virtual desk while dragging a window

Test: manual
Change-Id: Id3142bbe89caa2aa002f0b41f846bb885f6b56a2
Fixed: 1048315
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2037715Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738368}

ash/accelerators/accelerator_controller_impl.cc

@@ -68,6 +68,7 @@
 #include "ash/wm/desks/desks_controller.h"
 #include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/overview/overview_controller.h"
+#include "ash/wm/overview/overview_session.h"
 #include "ash/wm/screen_pinning_controller.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
 #include "ash/wm/tablet_mode/tablet_mode_window_manager.h"
@@ -150,6 +151,20 @@ enum class RotationAcceleratorAction {
   kMaxValue = kAlreadyAcceptedDialog,
 };
 
+bool IsAnyWindowDragged() {
+  OverviewController* overview_controller = Shell::Get()->overview_controller();
+  if (overview_controller->InOverviewSession() &&
+      overview_controller->overview_session()->IsAnyOverviewItemDragged()) {
+    return true;
+  }
+  for (aura::Window* window :
+       Shell::Get()->mru_window_tracker()->BuildMruWindowList(kActiveDesk)) {
+    if (WindowState::Get(window)->is_dragged())
+      return true;
+  }
+  return false;
+}
+
 void RecordRotationAcceleratorAction(const RotationAcceleratorAction& action) {
   UMA_HISTOGRAM_ENUMERATION("Ash.Accelerators.Rotation.Usage", action);
 }
@@ -368,6 +383,9 @@ void HandleNewDesk() {
 }
 
 void HandleRemoveCurrentDesk() {
+  if (IsAnyWindowDragged())
+    return;
+
   auto* desks_controller = DesksController::Get();
   if (!desks_controller->CanRemoveDesks()) {
     ShowToast(kVirtualDesksToastId,