[devicelab] migrate defines test to DriverTest (#68407)

Removes one-off handling for defines test and forces it to run through the DriverTest interface

dev/devicelab/bin/tasks/android_defines_test.dart

@@ -4,10 +4,10 @@
 
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
-import 'package:flutter_devicelab/tasks/defines_task.dart';
+import 'package:flutter_devicelab/tasks/integration_tests.dart';
 
 /// Verify that dart defines work on Android.
 Future<void> main() async {
   deviceOperatingSystem = DeviceOperatingSystem.android;
-  await task(runDartDefinesTask);
+  await task(dartDefinesTask());
 }

dev/devicelab/bin/tasks/ios_defines_test.dart

@@ -4,10 +4,10 @@
 
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
-import 'package:flutter_devicelab/tasks/defines_task.dart';
+import 'package:flutter_devicelab/tasks/integration_tests.dart';
 
 /// Verify that dart defines work on iOS.
 Future<void> main() async {
   deviceOperatingSystem = DeviceOperatingSystem.ios;
-  await task(runDartDefinesTask);
+  await task(dartDefinesTask());
 }

dev/devicelab/lib/tasks/defines_task.dart

-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'dart:io';
-
-import '../framework/adb.dart';
-import '../framework/task_result.dart';
-import '../framework/utils.dart';
-
-Future<TaskResult> runDartDefinesTask() async {
-  final Device device = await devices.workingDevice;
-  await device.unlock();
-  final String deviceId = device.deviceId;
-  final Directory testDirectory = dir('${flutterDirectory.path}/dev/integration_tests/ui');
-  await inDirectory<void>(testDirectory, () async {
-    await flutter('packages', options: <String>['get']);
-
-    await flutter('drive', options: <String>[
-      '--no-android-gradle-daemon',
-      '--verbose',
-      '-d',
-      deviceId,
-      '--dart-define=test.valueA=Example',
-      '--dart-define=test.valueB=Value',
-      'lib/defines.dart',
-    ]);
-  });
-
-  return TaskResult.success(<String, dynamic>{});
-}

dev/devicelab/lib/tasks/integration_tests.dart

@@ -127,6 +127,16 @@ TaskFunction createEndToEndKeyboardTextfieldTest() {
   );
 }
 
+TaskFunction dartDefinesTask() {
+  return DriverTest(
+    '${flutterDirectory.path}/dev/integration_tests/ui',
+    'lib/defines.dart', extraOptions: <String>[
+    '--dart-define=test.valueA=Example',
+    '--dart-define=test.valueB=Value',
+    ],
+  );
+}
+
 class DriverTest {
   DriverTest(
     this.testDirectory,