Migrate web_e2e_tests to null safety (#80628)

dev/integration_tests/web_e2e_tests/lib/text_editing_main.dart

@@ -7,7 +7,7 @@ import 'package:flutter/material.dart';
 void main() => runApp(const MyApp());
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key key}) : super(key: key);
+  const MyApp({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -20,9 +20,9 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatefulWidget {
-  const MyHomePage({Key key, this.title}) : super(key: key);
+  const MyHomePage({Key? key, this.title}) : super(key: key);
 
-  final String title;
+  final String? title;
 
   @override
   _MyHomePageState createState() => _MyHomePageState();
@@ -44,7 +44,7 @@ class _MyHomePageState extends State<MyHomePage> {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: Text(widget.title),
+        title: Text(widget.title ?? ''),
       ),
       body: Center(
         child: Column(

dev/integration_tests/web_e2e_tests/pubspec.yaml

@@ -2,7 +2,7 @@ name: web_e2e_tests
 publish_to: none
 
 environment:
-  sdk: ">=2.2.2 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:

dev/integration_tests/web_e2e_tests/test_driver/text_editing_integration.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
 import 'dart:html';
 import 'dart:js_util' as js_util;
 
@@ -39,7 +38,7 @@ void main() {
 
     // Change the value of the TextFormField.
     final TextFormField textFormField = tester.widget(finder);
-    textFormField.controller.text = 'New Value';
+    textFormField.controller?.text = 'New Value';
     // DOM element's value also changes.
     expect(input.value, 'New Value');
   });
@@ -67,7 +66,7 @@ void main() {
 
     // Change the value of the TextFormField.
     final TextFormField textFormField = tester.widget(finder);
-    textFormField.controller.text = 'New Value';
+    textFormField.controller?.text = 'New Value';
     // DOM element's value also changes.
     expect(input.value, 'New Value');
   });
@@ -225,8 +224,8 @@ void main() {
     expect(input.hasAttribute('readonly'), isTrue);
 
     // Make sure the entire text is selected.
-    TextRange range =
-        TextRange(start: input.selectionStart, end: input.selectionEnd);
+    TextRange? range =
+        TextRange(start: input.selectionStart!, end: input.selectionEnd!);
     expect(range.textInside(text), text);
 
     // Double tap to select the first word.
@@ -239,7 +238,7 @@ void main() {
     await gesture.up();
     await gesture.down(firstWordOffset);
     await gesture.up();
-    range = TextRange(start: input.selectionStart, end: input.selectionEnd);
+    range = TextRange(start: input.selectionStart!, end: input.selectionEnd!);
     expect(range.textInside(text), 'Lorem');
 
     // Double tap to select the last word.
@@ -252,14 +251,14 @@ void main() {
     await gesture.up();
     await gesture.down(lastWordOffset);
     await gesture.up();
-    range = TextRange(start: input.selectionStart, end: input.selectionEnd);
+    range = TextRange(start: input.selectionStart!, end: input.selectionEnd!);
     expect(range.textInside(text), 'amet');
   });
 }
 
 KeyboardEvent dispatchKeyboardEvent(
     EventTarget target, String type, Map<String, dynamic> args) {
-  final dynamic jsKeyboardEvent = js_util.getProperty(window, 'KeyboardEvent');
+  final Object jsKeyboardEvent = js_util.getProperty(window, 'KeyboardEvent') as Object;
   final List<dynamic> eventArgs = <dynamic>[
     type,
     args,

dev/integration_tests/web_e2e_tests/test_driver/text_editing_integration_test.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
 import 'package:integration_test/integration_test_driver.dart' as test;
 
 Future<void> main() async => test.integrationDriver();