Support clipBehavior changes in hot reload (#31761)

## Description

Make `_RenderCustomClip`'s `clipBehavior` non-final so we can update it during `updateRenderObject`. This will support `clipBehavior` changes in hot reload.

## Related Issues

Fixes #30863

## Tests

I added the following tests:

* ClipRect updates clipBehavior in updateRenderObject
* ClipRRect updates clipBehavior in updateRenderObject
* ClipOval updates clipBehavior in updateRenderObject
* ClipPath updates clipBehavior in updateRenderObject
* PhysicalModel updates clipBehavior in updateRenderObject
* PhysicalShape updates clipBehavior in updateRenderObject

packages/flutter/lib/src/rendering/layer.dart

@@ -1463,6 +1463,7 @@ class PhysicalModelLayer extends ContainerLayer {
   Clip get clipBehavior => _clipBehavior;
   Clip _clipBehavior;
   set clipBehavior(Clip value) {
+    assert(value != null);
     if (value != _clipBehavior) {
       _clipBehavior = value;
       markNeedsAddToScene();

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -1152,9 +1152,10 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox {
   _RenderCustomClip({
     RenderBox child,
     CustomClipper<T> clipper,
-    this.clipBehavior = Clip.antiAlias,
-  }) : _clipper = clipper,
-       assert(clipBehavior != null),
+    Clip clipBehavior = Clip.antiAlias,
+  }) : assert(clipBehavior != null),
+       _clipper = clipper,
+       _clipBehavior = clipBehavior,
        super(child);
 
   /// If non-null, determines which clip to use on the child.
@@ -1198,7 +1199,14 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox {
   T get _defaultClip;
   T _clip;
 
-  final Clip clipBehavior;
+  Clip get clipBehavior => _clipBehavior;
+  set clipBehavior(Clip value) {
+    if (value != _clipBehavior) {
+      _clipBehavior = value;
+      markNeedsPaint();
+    }
+  }
+  Clip _clipBehavior;
 
   @override
   void performLayout() {

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

@@ -594,7 +594,9 @@ class ClipRect extends SingleChildRenderObjectWidget {
 
   @override
   void updateRenderObject(BuildContext context, RenderClipRect renderObject) {
-    renderObject.clipper = clipper;
+    renderObject
+      ..clipper = clipper
+      ..clipBehavior = clipBehavior;
   }
 
   @override
@@ -661,6 +663,7 @@ class ClipRRect extends SingleChildRenderObjectWidget {
   void updateRenderObject(BuildContext context, RenderClipRRect renderObject) {
     renderObject
       ..borderRadius = borderRadius
+      ..clipBehavior = clipBehavior
       ..clipper = clipper;
   }
 
@@ -710,7 +713,9 @@ class ClipOval extends SingleChildRenderObjectWidget {
 
   @override
   void updateRenderObject(BuildContext context, RenderClipOval renderObject) {
-    renderObject.clipper = clipper;
+    renderObject
+      ..clipper = clipper
+      ..clipBehavior = clipBehavior;
   }
 
   @override
@@ -796,7 +801,9 @@ class ClipPath extends SingleChildRenderObjectWidget {
 
   @override
   void updateRenderObject(BuildContext context, RenderClipPath renderObject) {
-    renderObject.clipper = clipper;
+    renderObject
+      ..clipper = clipper
+      ..clipBehavior = clipBehavior;
   }
 
   @override
@@ -886,6 +893,7 @@ class PhysicalModel extends SingleChildRenderObjectWidget {
   void updateRenderObject(BuildContext context, RenderPhysicalModel renderObject) {
     renderObject
       ..shape = shape
+      ..clipBehavior = clipBehavior
       ..borderRadius = borderRadius
       ..elevation = elevation
       ..color = color
@@ -974,6 +982,7 @@ class PhysicalShape extends SingleChildRenderObjectWidget {
   void updateRenderObject(BuildContext context, RenderPhysicalShape renderObject) {
     renderObject
       ..clipper = clipper
+      ..clipBehavior = clipBehavior
       ..elevation = elevation
       ..color = color
       ..shadowColor = shadowColor;

packages/flutter/test/widgets/clip_test.dart

@@ -40,7 +40,75 @@ class ValueClipper<T> extends CustomClipper<T> {
   }
 }
 
+class _UpdateCountedClipRect extends ClipRect {
+  _UpdateCountedClipRect({Clip clipBehavior = Clip.antiAlias})
+    : super(clipBehavior: clipBehavior);
+}
+
+class _UpdateCountedClipRRect extends ClipRRect {
+  _UpdateCountedClipRRect({Clip clipBehavior = Clip.antiAlias})
+      : super(clipBehavior: clipBehavior, borderRadius: BorderRadius.circular(1.0));
+}
+
+class _UpdateCountedClipOval extends ClipOval {
+  _UpdateCountedClipOval({Clip clipBehavior = Clip.antiAlias})
+      : super(clipBehavior: clipBehavior);
+}
+
+class _UpdateCountedClipPath extends ClipPath {
+  _UpdateCountedClipPath({Clip clipBehavior = Clip.antiAlias})
+      : super(clipBehavior: clipBehavior);
+}
+
 void main() {
+  testWidgets('ClipRect updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(_UpdateCountedClipRect());
+
+    final RenderClipRect renderClip = tester.allRenderObjects.whereType<RenderClipRect>().first;
+
+    expect(renderClip.clipBehavior, equals(Clip.antiAlias));
+
+    await tester.pumpWidget(_UpdateCountedClipRect(clipBehavior: Clip.hardEdge));
+
+    expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+  });
+
+  testWidgets('ClipRRect updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(_UpdateCountedClipRRect());
+
+    final RenderClipRRect renderClip = tester.allRenderObjects.whereType<RenderClipRRect>().first;
+
+    expect(renderClip.clipBehavior, equals(Clip.antiAlias));
+
+    await tester.pumpWidget(_UpdateCountedClipRRect(clipBehavior: Clip.hardEdge));
+
+    expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+  });
+
+  testWidgets('ClipOval updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(_UpdateCountedClipOval());
+
+    final RenderClipOval renderClip = tester.allRenderObjects.whereType<RenderClipOval>().first;
+
+    expect(renderClip.clipBehavior, equals(Clip.antiAlias));
+
+    await tester.pumpWidget(_UpdateCountedClipOval(clipBehavior: Clip.hardEdge));
+
+    expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+  });
+
+  testWidgets('ClipPath updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(_UpdateCountedClipPath());
+
+    final RenderClipPath renderClip = tester.allRenderObjects.whereType<RenderClipPath>().first;
+
+    expect(renderClip.clipBehavior, equals(Clip.antiAlias));
+
+    await tester.pumpWidget(_UpdateCountedClipPath(clipBehavior: Clip.hardEdge));
+
+    expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+  });
+
   testWidgets('ClipPath', (WidgetTester tester) async {
     await tester.pumpWidget(
       ClipPath(

packages/flutter/test/widgets/physical_model_test.dart

@@ -10,7 +10,49 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+class _UpdateCountedPhysicalModel extends PhysicalModel {
+  _UpdateCountedPhysicalModel({Clip clipBehavior = Clip.none})
+    : super(clipBehavior: clipBehavior, color: Colors.red);
+}
+
+class _UpdateCountedPhysicalShape extends PhysicalShape {
+  _UpdateCountedPhysicalShape({Clip clipBehavior = Clip.none})
+      : super(clipBehavior: clipBehavior, color: Colors.red, clipper: ShapeBorderClipper(shape: CircleBorder()));
+}
+
 void main() {
+  testWidgets('PhysicalModel updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(home: _UpdateCountedPhysicalModel()),
+    );
+
+    final RenderPhysicalModel renderPhysicalModel = tester.allRenderObjects.whereType<RenderPhysicalModel>().first;
+
+    expect(renderPhysicalModel.clipBehavior, equals(Clip.none));
+
+    await tester.pumpWidget(
+      MaterialApp(home: _UpdateCountedPhysicalModel(clipBehavior: Clip.antiAlias)),
+    );
+
+    expect(renderPhysicalModel.clipBehavior, equals(Clip.antiAlias));
+  });
+
+  testWidgets('PhysicalShape updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(home: _UpdateCountedPhysicalShape()),
+    );
+
+    final RenderPhysicalShape renderPhysicalShape = tester.allRenderObjects.whereType<RenderPhysicalShape>().first;
+
+    expect(renderPhysicalShape.clipBehavior, equals(Clip.none));
+
+    await tester.pumpWidget(
+      MaterialApp(home: _UpdateCountedPhysicalShape(clipBehavior: Clip.antiAlias)),
+    );
+
+    expect(renderPhysicalShape.clipBehavior, equals(Clip.antiAlias));
+  });
+
   testWidgets('PhysicalModel - creates a physical model layer when it needs compositing', (WidgetTester tester) async {
     debugDisableShadows = false;
     await tester.pumpWidget(