cros: Add toast for visible on all desks window in overview.

When a user tries to drag a visible on all desks window to a specific
desk in overview mode, they are unable to. Currently there is no visual
indicator that nothing happened.

This CL adds a toast for when this happens and also prevents the desks
mini views from highlighting when a user drags a visible on all desks
window over the mini views.

Test: manual
Bug: 1163697
Change-Id: I43acbfb9b90567dbeef294ac97c0e6cc5af33bdd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2616319Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Jeremy Chinsen <chinsenj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842191}

ash/ash_strings.grd

@@ -1359,6 +1359,9 @@ This file contains the strings for ash.
       <message name="IDS_ASH_OVERVIEW_WINDOW_CLOSING_A11Y_ALERT" desc="The accessibility alert read by screen readers to alert the user that a window in overview mode is closing.">
         Window <ph name="WINDOW_TITILE">$1<ex>1</ex></ph> closed.
       </message>
+      <message name="IDS_ASH_OVERVIEW_VISIBLE_ON_ALL_DESKS_TOAST" desc="The text for the toast that appears when user tries to drag a visible on all desks window to a desk.">
+        Already assigned to all desks.
+      </message>
 
       <!-- Virtual Desks -->
       <message name="IDS_ASH_DESKS_NEW_DESK_BUTTON" desc="The label of the new virtual desk (a.k.a. workspaces) button.">

ash/ash_strings_grd/IDS_ASH_OVERVIEW_VISIBLE_ON_ALL_DESKS_TOAST.png.sha1

+0feb78aa3efb3b45ffd5e7ec3c2ad58b3a51026a
\ No newline at end of file

ash/wm/desks/desks_controller.cc

@@ -496,7 +496,6 @@ bool DesksController::MoveWindowFromActiveDeskTo(
     if (source == DesksMoveWindowFromActiveDeskSource::kDragAndDrop) {
       // Since a visible on all desks window is on all desks, prevent users from
       // moving them manually in overview.
-      // TODO(chinsenj): Add a UX indication for users.
       return false;
     } else if (source == DesksMoveWindowFromActiveDeskSource::kShortcut) {
       window->SetProperty(aura::client::kVisibleOnAllWorkspacesKey, false);

ash/wm/overview/overview_grid.cc

@@ -22,6 +22,8 @@
 #include "ash/rotator/screen_rotation_animator.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
+#include "ash/system/toast/toast_manager_impl.h"
 #include "ash/wallpaper/wallpaper_controller_impl.h"
 #include "ash/wm/desks/desk_mini_view.h"
 #include "ash/wm/desks/desk_name_view.h"
@@ -56,6 +58,7 @@
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/throughput_tracker.h"
 #include "ui/gfx/geometry/vector2d_f.h"
@@ -90,6 +93,12 @@ constexpr base::TimeDelta kOcclusionUnpauseDurationForScroll =
 constexpr base::TimeDelta kOcclusionUnpauseDurationForRotation =
     base::TimeDelta::FromMilliseconds(300);
 
+// Toast id for the toast that is displayed when a user tries to move a window
+// that is visible on all desks to another desk.
+constexpr char kMoveVisibleOnAllDesksWindowToastId[] =
+    "ash.wm.overview.move_visible_on_all_desks_window_toast";
+constexpr int kToastDurationMs = 2500;
+
 // Histogram names for overview enter/exit smoothness in clamshell,
 // tablet mode and splitview.
 constexpr char kOverviewEnterClamshellHistogram[] =
@@ -1358,19 +1367,33 @@ bool OverviewGrid::MaybeDropItemOnDeskMiniView(
     OverviewItem* drag_item) {
   DCHECK(desks_util::ShouldDesksBarBeCreated());
 
+  aura::Window* const dragged_window = drag_item->GetWindow();
+  const bool dragged_window_is_visible_on_all_desks =
+      dragged_window &&
+      dragged_window->GetProperty(aura::client::kVisibleOnAllWorkspacesKey);
   // End the drag for the DesksBarView.
   if (!IntersectsWithDesksBar(screen_location,
-                              /*update_desks_bar_drag_details=*/true,
+                              /*update_desks_bar_drag_details=*/
+                              !dragged_window_is_visible_on_all_desks,
                               /*for_drop=*/true)) {
     return false;
   }
 
+  if (dragged_window_is_visible_on_all_desks) {
+    // Show toast since items that are visible on all desks should not be able
+    // to be unassigned during overview.
+    Shell::Get()->toast_manager()->Show(ToastData(
+        kMoveVisibleOnAllDesksWindowToastId,
+        l10n_util::GetStringUTF16(IDS_ASH_OVERVIEW_VISIBLE_ON_ALL_DESKS_TOAST),
+        kToastDurationMs, base::nullopt));
+    return false;
+  }
+
   auto* desks_controller = DesksController::Get();
   for (auto* mini_view : desks_bar_view_->mini_views()) {
     if (!mini_view->IsPointOnMiniView(screen_location))
       continue;
 
-    aura::Window* const dragged_window = drag_item->GetWindow();
     Desk* const target_desk = mini_view->desk();
     if (target_desk == desks_controller->active_desk())
       return false;

ash/wm/overview/overview_window_drag_controller.cc

@@ -31,6 +31,7 @@
 #include "base/metrics/histogram_functions.h"
 #include "base/numerics/ranges.h"
 #include "base/numerics/safe_conversions.h"
+#include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/display/display.h"
@@ -79,6 +80,13 @@ bool GetVirtualDesksBarEnabled(OverviewItem* item) {
          item->overview_grid()->IsDesksBarViewActive();
 }
 
+// Returns whether |item|'s window is visible on all desks.
+bool DraggedItemIsVisibleOnAllDesks(OverviewItem* item) {
+  aura::Window* const dragged_window = item->GetWindow();
+  return dragged_window &&
+         dragged_window->GetProperty(aura::client::kVisibleOnAllWorkspacesKey);
+}
+
 // Returns the scaled-down size of the dragged item that should be used when
 // it's dragged over the DesksBarView that belongs to |overview_grid|.
 // |window_original_size| is the size of the item's window before it was scaled
@@ -520,10 +528,12 @@ void OverviewWindowDragController::ContinueNormalDrag(
 
     if (desks_bar_data.shrink_bounds.Contains(location_in_screen)) {
       // Update the mini views borders by checking if |location_in_screen|
-      // intersects.
+      // intersects. Only update the borders if the dragged item is not visible
+      // on all desks.
       overview_grid->IntersectsWithDesksBar(
           gfx::ToRoundedPoint(location_in_screen),
-          /*update_desks_bar_drag_details=*/true, /*for_drop=*/false);
+          /*update_desks_bar_drag_details=*/
+          !DraggedItemIsVisibleOnAllDesks(item_), /*for_drop=*/false);
 
       float value = 0.f;
       if (centerpoint.y() < desks_bar_data.desks_bar_bounds.y() ||