overview: Enable overview new focus

This enables a new view based focus style that has a lot less
custom logic than the existing way. The old code will remain until
branch in case we want to disable.

Fixes one last bug where activating a view will stack it on top.
However, for overview items we want the view to remain underneath
the actual window.

Test: trybots
Test: manual
Bug: b:325335020
Change-Id: Ia0c7989174f518923e389a000896433348626ac0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5646323
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1320616}

ash/accessibility/magnifier/docked_magnifier_controller_unittest.cc

@@ -513,6 +513,14 @@ TEST_F(DockedMagnifierTest, DisplaysWorkAreasOverviewMode) {
 }
 
 TEST_F(DockedMagnifierTest, OverviewTabbing) {
+  // In production code, `DockedMagnifierController::CenterOnPoint()` is called
+  // via an extension function. This code path will not be triggered in ash unit
+  // tests.
+  if (features::IsOverviewNewFocusEnabled()) {
+    GTEST_SKIP() << "Overview new focus uses `views::View::RequestFocus()` and "
+                    "has no custom magnifier logic anymore.";
+  }
+
   auto window = CreateTestWindow();
   controller()->SetEnabled(true);
 

ash/constants/ash_features.cc

@@ -2294,7 +2294,7 @@ BASE_FEATURE(kOverviewDeskNavigation,
 
 BASE_FEATURE(kOverviewNewFocus,
              "OverviewNewFocus",
-             base::FEATURE_DISABLED_BY_DEFAULT);
+             base::FEATURE_ENABLED_BY_DEFAULT);
 
 // Enables Jelly colors and components to appear in the Parent Access Widget
 // if jelly-colors is also enabled.

ash/wm/overview/overview_focus_cycler.cc

@@ -95,6 +95,31 @@ class ScopedActivatable : public views::WidgetObserver {
     observation_.Reset();
   }
 
+  void OnWidgetActivationChanged(views::Widget* widget, bool active) override {
+    if (!active) {
+      return;
+    }
+
+    // If an overview item received focus, we need to restack the original
+    // window above the overview item widget, otherwise the overview backdrop
+    // would end up covering the original window.
+    auto* item_view =
+        views::AsViewClass<OverviewItemView>(widget->GetContentsView());
+    if (!item_view) {
+      return;
+    }
+
+    OverviewItemBase* item = item_view->GetOverviewItem();
+    if (!item) {
+      return;
+    }
+
+    aura::Window* parent = widget->GetNativeWindow()->parent();
+    if (parent == item->GetWindow()->parent()) {
+      parent->StackChildAbove(item->GetWindow(), widget->GetNativeWindow());
+    }
+  }
+
  private:
   base::ScopedObservation<views::Widget, views::WidgetObserver> observation_{
       this};

ash/wm/overview/overview_session.cc

@@ -1053,16 +1053,8 @@ aura::Window* OverviewSession::GetFocusedWindow() const {
     return nullptr;
   }
 
-  const views::Widget* item_widget = item_view->GetWidget();
-  for (const std::unique_ptr<OverviewGrid>& overview_grid : grid_list_) {
-    for (const auto& overview_item : overview_grid->window_list()) {
-      if (overview_item->item_widget() == item_widget) {
-        return overview_item->GetWindow();
-      }
-    }
-  }
-
-  return nullptr;
+  OverviewItemBase* item = item_view->GetOverviewItem();
+  return item ? item->GetWindow() : nullptr;
 }
 
 void OverviewSession::SuspendReposition() {