Add Gamepad support for the activation action (#49987)

packages/flutter/lib/src/widgets/app.dart

@@ -847,6 +847,7 @@ class WidgetsApp extends StatefulWidget {
     // Activation
     LogicalKeySet(LogicalKeyboardKey.enter): const Intent(ActivateAction.key),
     LogicalKeySet(LogicalKeyboardKey.space): const Intent(ActivateAction.key),
+    LogicalKeySet(LogicalKeyboardKey.gameButtonA): const Intent(ActivateAction.key),
 
     // Keyboard traversal.
     LogicalKeySet(LogicalKeyboardKey.tab): const Intent(NextFocusAction.key),

packages/flutter/test/widgets/app_test.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
@@ -96,6 +97,48 @@ void main() {
     expect(action.calls, equals(1));
   });
 
+  testWidgets('WidgetsApp default activation key mappings work', (WidgetTester tester) async {
+    bool checked = false;
+
+    await tester.pumpWidget(
+      WidgetsApp(
+        builder: (BuildContext context, Widget child) {
+          return Material(
+            child: Checkbox(
+              value: checked,
+              autofocus: true,
+              onChanged: (bool value) {
+                checked = value;
+              },
+            ),
+          );
+        },
+        color: const Color(0xFF123456),
+      ),
+    );
+    await tester.pump();
+
+    // Test three default buttons for the activation action.
+    await tester.sendKeyEvent(LogicalKeyboardKey.space);
+    await tester.pumpAndSettle();
+    expect(checked, isTrue);
+
+    // Only space is used as an activation key on web.
+    if (kIsWeb) {
+      return;
+    }
+
+    checked = false;
+    await tester.sendKeyEvent(LogicalKeyboardKey.enter);
+    await tester.pumpAndSettle();
+    expect(checked, isTrue);
+
+    checked = false;
+    await tester.sendKeyEvent(LogicalKeyboardKey.gameButtonA);
+    await tester.pumpAndSettle();
+    expect(checked, isTrue);
+  });
+
   group('error control test', () {
     Future<void> expectFlutterError({
       GlobalKey<NavigatorState> key,