Fixes for upcoming changes to avoid_classes_with_only_static_members (#86744)

dev/integration_tests/flutter_gallery/lib/demo/shrine/model/app_state_model.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter_gallery/demo/shrine/model/product.dart';
-import 'package:flutter_gallery/demo/shrine/model/products_repository.dart';
+import 'package:flutter_gallery/demo/shrine/model/products_repository.dart' as product_repository;
 import 'package:scoped_model/scoped_model.dart';
 
 double _salesTaxRate = 0.06;
@@ -99,7 +99,7 @@ class AppStateModel extends Model {
 
   // Loads the list of available products from the repo.
   void loadProducts() {
-    _availableProducts = ProductsRepository.loadProducts(Category.all);
+    _availableProducts = product_repository.loadProducts(Category.all);
     notifyListeners();
   }
 

packages/flutter_driver/lib/src/common/fuchsia_compat.dart

@@ -83,6 +83,10 @@ Future<PortForwarder> _dummyPortForwardingFunction(
 /// `FUCHSIA_SSH_CONFIG` variables must be set. If run on a Fuchsia device, will
 /// connect locally without need for environment variables.
 class FuchsiaCompat {
+  // This class is not meant to be instantiated or extended; this constructor
+  // prevents instantiation and extension.
+  FuchsiaCompat._();
+
   static void _init() {
     fuchsiaPortForwardingFunction = _dummyPortForwardingFunction;
   }

packages/flutter_test/lib/src/event_simulation.dart

@@ -26,6 +26,10 @@ String _keyLabel(LogicalKeyboardKey key) {
 /// A class that serves as a namespace for a bunch of keyboard-key generation
 /// utilities.
 class KeyEventSimulator {
+  // This class is not meant to be instantiated or extended; this constructor
+  // prevents instantiation and extension.
+  KeyEventSimulator._();
+
   // Look up a synonym key, and just return the left version of it.
   static LogicalKeyboardKey _getKeySynonym(LogicalKeyboardKey origKey) {
     if (origKey == LogicalKeyboardKey.shift) {