Added a devicelab test for vulkan validation layers (flutter#134685)

This makes sure validation layers are being used and that there are no
validation errors

fixes flutter#134175

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we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

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Author: gaaclarke

.ci.yaml

@@ -1567,6 +1567,16 @@ targets:
       - bin/**
       - .ci.yaml
 
+  - name: Linux_android hello_world_impeller
+    recipe: devicelab/devicelab_drone
+    presubmit: false
+    bringup: true
+    timeout: 60
+    properties:
+      tags: >
+        ["devicelab", "android", "linux"]
+      task_name: hello_world_impeller
+
   - name: Linux_android android_defines_test
     recipe: devicelab/devicelab_drone
     presubmit: true

TESTOWNERS

@@ -135,6 +135,7 @@
 /dev/devicelab/bin/tasks/fullscreen_textfield_perf__timeline_summary.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/hello_world__memory.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/hello_world_android__compile.dart @zanderso @flutter/tool
+/dev/devicelab/bin/tasks/hello_world_impeller.dart @gaaclarke @flutter/engine
 /dev/devicelab/bin/tasks/home_scroll_perf__timeline_summary.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart @eliasyishak @flutter/tool
 /dev/devicelab/bin/tasks/hybrid_android_views_integration_test.dart @stuartmorgan @flutter/plugin

dev/devicelab/bin/tasks/hello_world_impeller.dart

@@ -0,0 +1,81 @@
+// 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:async' show Completer, StreamSubscription;
+import 'dart:io' show Directory, Process;
+
+import 'package:flutter_devicelab/framework/devices.dart'
+    show Device, DeviceOperatingSystem, deviceOperatingSystem, devices;
+import 'package:flutter_devicelab/framework/framework.dart' show task;
+import 'package:flutter_devicelab/framework/task_result.dart' show TaskResult;
+import 'package:flutter_devicelab/framework/utils.dart'
+    show dir, flutter, flutterDirectory, inDirectory, startFlutter;
+import 'package:path/path.dart' as path;
+
+Future<TaskResult> run() async {
+  deviceOperatingSystem = DeviceOperatingSystem.android;
+  final Device device = await devices.workingDevice;
+  await device.unlock();
+  final Directory appDir =
+      dir(path.join(flutterDirectory.path, 'examples/hello_world'));
+
+  bool isUsingValidationLayers = false;
+  bool hasValidationErrors = false;
+  int impellerBackendCount = 0;
+  final Completer<void> didReceiveBackendMessage = Completer<void>();
+
+  await inDirectory(appDir, () async {
+    await flutter('packages', options: <String>['get']);
+
+    final StreamSubscription<String> adb = device.logcat.listen(
+      (String data) {
+        if (data.contains('Using the Impeller rendering backend')) {
+          // Sometimes more than one of these will be printed out if there is a
+          // fallback.
+          if (!didReceiveBackendMessage.isCompleted) {
+            didReceiveBackendMessage.complete();
+          }
+          impellerBackendCount += 1;
+        }
+        if (data.contains(
+            'Using the Impeller rendering backend (Vulkan with Validation Layers)')) {
+          isUsingValidationLayers = true;
+        }
+        // "ImpellerValidationBreak" comes from the engine:
+        // https://github.com/flutter/engine/blob/4160ebacdae2081d6f3160432f5f0dd87dbebec1/impeller/base/validation.cc#L40
+        if (data.contains('ImpellerValidationBreak')) {
+          hasValidationErrors = true;
+        }
+      },
+    );
+
+    final Process process = await startFlutter(
+      'run',
+      options: <String>[
+        '--enable-impeller',
+        '-d',
+        device.deviceId,
+      ],
+    );
+
+    await didReceiveBackendMessage.future;
+    // Since we are waiting for the lack of errors, there is no determinate
+    // amount of time we can wait.
+    await Future<void>.delayed(const Duration(seconds: 30));
+    process.stdin.write('q');
+    await adb.cancel();
+  });
+
+  if (!isUsingValidationLayers || impellerBackendCount != 1) {
+    return TaskResult.failure('Not using Vulkan validation layers.');
+  }
+  if (hasValidationErrors){
+    return TaskResult.failure('Impeller validation errors detected.');
+  }
+  return TaskResult.success(null);
+}
+
+Future<void> main() async {
+  await task(run);
+}