Add tiles_scroll_perf test (#19833)

dev/devicelab/bin/tasks/tiles_scroll_perf_timeline_summary.dart

+// Copyright 2016 The Chromium 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';
+
+import 'package:flutter_devicelab/tasks/perf_tests.dart';
+import 'package:flutter_devicelab/framework/adb.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+
+Future<Null> main() async {
+  deviceOperatingSystem = DeviceOperatingSystem.android;
+  await task(createTilesScrollPerfTest());
+}
+

dev/devicelab/lib/tasks/perf_tests.dart

@@ -22,6 +22,14 @@ TaskFunction createComplexLayoutScrollPerfTest() {
   ).run;
 }
 
+TaskFunction createTilesScrollPerfTest() {
+  return new PerfTest(
+    '${flutterDirectory.path}/dev/benchmarks/complex_layout',
+    'test_driver/scroll_perf.dart',
+    'tiles_scroll_perf',
+  ).run;
+}
+
 TaskFunction createComplexLayoutScrollMemoryTest() {
   return new MemoryTest(
     '${flutterDirectory.path}/dev/benchmarks/complex_layout',