Allow wrapping CheckBox in Semantics (#15259)

packages/flutter/lib/src/material/toggleable.dart

@@ -329,7 +329,6 @@ abstract class RenderToggleable extends RenderConstrainedBox {
   void describeSemanticsConfiguration(SemanticsConfiguration config) {
     super.describeSemanticsConfiguration(config);
 
-    config.isSemanticBoundary = true;
     config.isEnabled = isInteractive;
     if (isInteractive)
       config.onTap = _handleTap;

packages/flutter/test/material/checkbox_test.dart

@@ -11,6 +11,10 @@ import 'package:flutter/material.dart';
 import '../widgets/semantics_tester.dart';
 
 void main() {
+  setUp(() {
+    debugResetSemanticsIdCounter();
+  });
+
   testWidgets('CheckBox semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
 
@@ -103,6 +107,41 @@ void main() {
     semantics.dispose();
   });
 
+  testWidgets('Can wrap CheckBox with Semantics', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(new Material(
+      child: new Semantics(
+        label: 'foo',
+        textDirection: TextDirection.ltr,
+        child: new Checkbox(
+          value: false,
+          onChanged: (bool b) { },
+        ),
+      ),
+    ));
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+      children: <TestSemantics>[
+        new TestSemantics.rootChild(
+          id: 1,
+          label: 'foo',
+          textDirection: TextDirection.ltr,
+          flags: <SemanticsFlag>[
+            SemanticsFlag.hasCheckedState,
+            SemanticsFlag.hasEnabledState,
+            SemanticsFlag.isEnabled,
+          ],
+          actions: <SemanticsAction>[
+            SemanticsAction.tap,
+          ],
+        ),
+      ],
+    ), ignoreRect: true, ignoreTransform: true));
+
+    semantics.dispose();
+  });
+
   testWidgets('CheckBox tristate: true', (WidgetTester tester) async {
     bool checkBoxValue;