Revert "[web] switch from .didGain/LoseAccessibilityFocus to .focus" (#…

…53679)

Reverts #53360

Breaking google3 in b/350131288.

There is a test that does something like the following, to check if a radio button is selected.

```dart
      // Send a bunch of tabs to focus on the correct radio button
      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
      await tester.pump();
      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
      await tester.pump();
      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
      await tester.pump();

      // Toggle the radio button with space
      await tester.sendKeyEvent(LogicalKeyboardKey.space);
      await tester.pump();

      final selectedRadio =
          tester.widget<Radio<bool>>(find.byType(Radio<bool>).at(1));
      expect(selectedRadio.value, isTrue);
```

After this commit, the above test fails. See the linked bug above for more details.

lib/ui/semantics.dart

@@ -220,9 +220,6 @@ class SemanticsAction {
   /// must immediately become editable, opening a virtual keyboard, if needed.
   /// Buttons must respond to tap/click events from the keyboard.
   ///
-  /// Widget reaction to this action must be idempotent. It is possible to
-  /// receive this action more than once, or when the widget is already focused.
-  ///
   /// Focus behavior is specific to the platform and to the assistive technology
   /// used. Typically on desktop operating systems, such as Windows, macOS, and
   /// Linux, moving accessibility focus will also move the input focus. On

lib/web_ui/lib/src/engine/dom.dart

@@ -2753,30 +2753,6 @@ DomCompositionEvent createDomCompositionEvent(String type,
   }
 }
 
-/// This is a pseudo-type for DOM elements that have the boolean `disabled`
-/// property.
-///
-/// This type cannot be part of the actual type hierarchy because each DOM type
-/// defines its `disabled` property ad hoc, without inheriting it from a common
-/// type, e.g. [DomHTMLInputElement] and [DomHTMLTextAreaElement].
-///
-/// To use, simply cast any element known to have the `disabled` property to
-/// this type using `as DomElementWithDisabledProperty`, then read and write
-/// this property as normal.
-@JS()
-@staticInterop
-class DomElementWithDisabledProperty extends DomHTMLElement {}
-
-extension DomElementWithDisabledPropertyExtension on DomElementWithDisabledProperty {
-  @JS('disabled')
-  external JSBoolean? get _disabled;
-  bool? get disabled => _disabled?.toDart;
-
-  @JS('disabled')
-  external set _disabled(JSBoolean? value);
-  set disabled(bool? value) => _disabled = value?.toJS;
-}
-
 @JS()
 @staticInterop
 class DomHTMLInputElement extends DomHTMLElement {}

lib/web_ui/lib/src/engine/semantics/focusable.dart

@@ -81,6 +81,9 @@ typedef _FocusTarget = ({
 
   /// The listener for the "focus" DOM event.
   DomEventListener domFocusListener,
+
+  /// The listener for the "blur" DOM event.
+  DomEventListener domBlurListener,
 });
 
 /// Implements accessibility focus management for arbitrary elements.
@@ -132,6 +135,7 @@ class AccessibilityFocusManager {
         semanticsNodeId: semanticsNodeId,
         element: previousTarget.element,
         domFocusListener: previousTarget.domFocusListener,
+        domBlurListener: previousTarget.domBlurListener,
       );
       return;
     }
@@ -144,12 +148,14 @@ class AccessibilityFocusManager {
     final _FocusTarget newTarget = (
       semanticsNodeId: semanticsNodeId,
       element: element,
-      domFocusListener: createDomEventListener((_) => _didReceiveDomFocus()),
+      domFocusListener: createDomEventListener((_) => _setFocusFromDom(true)),
+      domBlurListener: createDomEventListener((_) => _setFocusFromDom(false)),
     );
     _target = newTarget;
 
     element.tabIndex = 0;
     element.addEventListener('focus', newTarget.domFocusListener);
+    element.addEventListener('blur', newTarget.domBlurListener);
   }
 
   /// Stops managing the focus of the current element, if any.
@@ -164,9 +170,10 @@ class AccessibilityFocusManager {
     }
 
     target.element.removeEventListener('focus', target.domFocusListener);
+    target.element.removeEventListener('blur', target.domBlurListener);
   }
 
-  void _didReceiveDomFocus() {
+  void _setFocusFromDom(bool acquireFocus) {
     final _FocusTarget? target = _target;
 
     if (target == null) {
@@ -177,7 +184,9 @@ class AccessibilityFocusManager {
 
     EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
       target.semanticsNodeId,
-      ui.SemanticsAction.focus,
+      acquireFocus
+        ? ui.SemanticsAction.didGainAccessibilityFocus
+        : ui.SemanticsAction.didLoseAccessibilityFocus,
       null,
     );
   }
@@ -220,7 +229,7 @@ class AccessibilityFocusManager {
       // a dialog, and nothing else in the dialog is focused. The Flutter
       // framework expects that the screen reader will focus on the first (in
       // traversal order) focusable element inside the dialog and send a
-      // SemanticsAction.focus action. Screen readers on the web do not do
+      // didGainAccessibilityFocus action. Screen readers on the web do not do
       // that, and so the web engine has to implement this behavior directly. So
       // the dialog will look for a focusable element and request focus on it,
       // but now there may be a race between this method unsetting the focus and

lib/web_ui/lib/src/engine/semantics/semantics.dart

@@ -2218,6 +2218,8 @@ class EngineSemantics {
       'mousemove',
       'mouseleave',
       'mouseup',
+      'keyup',
+      'keydown',
     ];
 
     if (pointerEventTypes.contains(event.type)) {