Do not paint a description label when rendering an integration test (#153875)

Fixes https://github.com/flutter/flutter/issues/153624

packages/flutter_test/lib/src/binding.dart

@@ -1832,7 +1832,13 @@ class LiveTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
     fontSize: 10.0,
   );
 
-  void _setDescription(String value) {
+  /// Label describing the test.
+  @visibleForTesting
+  TextPainter? get label => _label;
+
+  /// Set a description label that is drawn into the test output.
+  @protected
+  void setLabel(String value) {
     if (value.isEmpty) {
       _label = null;
       return;
@@ -2033,7 +2039,7 @@ class LiveTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
   }) {
     assert(!inTest);
     _inTest = true;
-    _setDescription(description);
+    setLabel(description);
     return _runTest(testBody, invariantTester, description);
   }
 

packages/integration_test/lib/integration_test.dart

@@ -244,6 +244,11 @@ https://docs.flutter.dev/testing/integration-tests
     results[description] ??= _success;
   }
 
+  // Do not paint a description label because it could show up in screenshots
+  // of the integration test.
+  @override
+  void setLabel(String value) {}
+
   vm.VmService? _vmService;
 
   /// Initialize the [vm.VmService] settings for the timeline.

packages/integration_test/test/binding_test.dart

@@ -130,6 +130,10 @@ Future<void> main() async {
 
       expect(find.byType(RepaintBoundary), findsOneWidget);
     });
+
+    testWidgets('integration test has no label', (WidgetTester tester) async {
+      expect(binding.label, null);
+    });
   });
 
   tearDownAll(() async {