Fix ink highlight effect of RawChip (#28653)

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

@@ -1625,10 +1625,11 @@ class _RawChipState extends State<RawChip> with TickerProviderStateMixin<RawChip
       animationDuration: pressedAnimationDuration,
       shape: shape,
       clipBehavior: widget.clipBehavior,
-      child: InkResponse(
+      child: InkWell(
         onTap: canTap ? _handleTap : null,
         onTapDown: canTap ? _handleTapDown : null,
         onTapCancel: canTap ? _handleTapCancel : null,
+        customBorder: shape,
         child: AnimatedBuilder(
           animation: Listenable.merge(<Listenable>[selectController, enableController]),
           builder: (BuildContext context, Widget child) {

packages/flutter/test/material/chip_test.dart

@@ -1649,4 +1649,19 @@ void main() {
       const Offset(4, 4),
     ]));
   });
+
+  testWidgets('Chips should use InkWell instead of InkResponse.', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/28646
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: ActionChip(
+            onPressed: (){},
+            label: const Text('action chip'),
+          ),
+        ),
+      ),
+    );
+    expect(find.byType(InkWell), findsOneWidget);
+  });
 }