Adding first semantics perf test (#10649)

* Adding first semantics perf test

* review commnts and analyzer fixes

* fix analyzer warning

dev/benchmarks/complex_layout/test_driver/semantics_perf.dart

@@ -0,0 +1,11 @@
+// Copyright 2017 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 'package:flutter_driver/driver_extension.dart';
+import 'package:complex_layout/main.dart' as app;
+
+void main() {
+  enableFlutterDriverExtension();
+  app.main();
+}

dev/benchmarks/complex_layout/test_driver/semantics_perf_test.dart

@@ -0,0 +1,43 @@
+// Copyright 2017 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 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter_driver/flutter_driver.dart';
+import 'package:path/path.dart' as p;
+import 'package:test/test.dart';
+
+void main() {
+  group('semantics performance test', () {
+    FlutterDriver driver;
+
+    setUpAll(() async {
+      driver = await FlutterDriver.connect(printCommunication: true);
+    });
+
+    tearDownAll(() async {
+      if (driver != null)
+        driver.close();
+    });
+
+    test('inital tree creation', () async {
+      // Let app become fully idle.
+      await new Future<Null>.delayed(const Duration(seconds: 1));
+
+      final Timeline timeline = await driver.traceAction(() async {
+        expect(await driver.setSemantics(true), isTrue);
+      });
+
+      final Iterable<TimelineEvent> semanticsEvents = timeline.events.where((TimelineEvent event) => event.name == "Semantics");
+      if (semanticsEvents.length != 1)
+        fail('Expected exactly one semantics event, got ${semanticsEvents.length}');
+      final Duration semanticsTreeCreation = semanticsEvents.first.duration;
+
+      final String json = JSON.encode(<String, dynamic>{'initialSemanticsTreeCreation': semanticsTreeCreation.inMilliseconds});
+      new File(p.join(testOutputsDirectory, 'complex_layout_semantics_perf.json')).writeAsStringSync(json);
+    });
+  });
+}

dev/devicelab/bin/tasks/complex_layout_semantics_perf.dart

@@ -0,0 +1,38 @@
+// Copyright (c) 2017 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 'package:flutter_devicelab/framework/adb.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/framework/utils.dart';
+import 'package:path/path.dart' as p;
+
+void main() {
+  task(() async {
+    deviceOperatingSystem = DeviceOperatingSystem.android;
+
+    final Device device = await devices.workingDevice;
+    await device.unlock();
+    final String deviceId = device.deviceId;
+    await flutter('packages', options: <String>['get']);
+
+    final String complexLayoutPath = p.join(flutterDirectory.path, 'dev', 'benchmarks', 'complex_layout');
+
+    await inDirectory(complexLayoutPath, () async {
+      await flutter('drive', options: <String>[
+        '-v',
+        '--profile',
+        '--trace-startup', // Enables "endless" timeline event buffering.
+        '-t',
+        p.join(complexLayoutPath, 'test_driver', 'semantics_perf.dart'),
+        '-d',
+        deviceId,
+      ]);
+    });
+
+    final String dataPath = p.join(complexLayoutPath, 'build', 'complex_layout_semantics_perf.json');
+    return new TaskResult.successFromFile(file(dataPath), benchmarkScoreKeys: <String>[
+      'initialSemanticsTreeCreation',
+    ]);
+  });
+}

dev/devicelab/manifest.yaml

@@ -133,6 +133,13 @@ tasks:
     required_agent_capabilities: ["linux/android"]
     flaky: true
 
+  complex_layout_semantics_perf:
+    description: >
+      Measures duration of building the initial semantics tree.
+    stage: devicelab
+    required_agent_capabilities: ["linux/android"]
+    flaky: true
+
   # iOS on-device tests
 
   channels_integration_test_ios:

packages/flutter_driver/lib/src/driver.dart

@@ -21,6 +21,7 @@ import 'gesture.dart';
 import 'health.dart';
 import 'message.dart';
 import 'render_tree.dart';
+import 'semantics.dart';
 import 'timeline.dart';
 
 /// Timeline stream identifier.
@@ -383,6 +384,15 @@ class FlutterDriver {
     return GetTextResult.fromJson(await _sendCommand(new GetText(finder, timeout: timeout))).text;
   }
 
+  /// Turns semantics on or off in the Flutter app under test.
+  ///
+  /// Returns `true` when the call actually changed the state from on to off or
+  /// vice versa.
+  Future<bool> setSemantics(bool enabled, { Duration timeout: _kShortTimeout }) async {
+    final SetSemanticsResult result = SetSemanticsResult.fromJson(await _sendCommand(new SetSemantics(enabled, timeout: timeout)));
+    return result.changedState;
+  }
+
   /// Take a screenshot.  The image will be returned as a PNG.
   Future<List<int>> screenshot({ Duration timeout }) async {
     timeout ??= _kLongTimeout;

packages/flutter_driver/lib/src/extension.dart

@@ -8,7 +8,7 @@ import 'package:meta/meta.dart';
 
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/rendering.dart' show RendererBinding;
+import 'package:flutter/rendering.dart' show RendererBinding, SemanticsHandle;
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -20,6 +20,7 @@ import 'gesture.dart';
 import 'health.dart';
 import 'message.dart';
 import 'render_tree.dart';
+import 'semantics.dart';
 
 const String _extensionMethodName = 'driver';
 const String _extensionMethod = 'ext.flutter.$_extensionMethodName';
@@ -70,6 +71,7 @@ class FlutterDriverExtension {
       'tap': _tap,
       'get_text': _getText,
       'set_frame_sync': _setFrameSync,
+      'set_semantics': _setSemantics,
       'scroll': _scroll,
       'scrollIntoView': _scrollIntoView,
       'waitFor': _waitFor,
@@ -82,6 +84,7 @@ class FlutterDriverExtension {
       'tap': (Map<String, String> params) => new Tap.deserialize(params),
       'get_text': (Map<String, String> params) => new GetText.deserialize(params),
       'set_frame_sync': (Map<String, String> params) => new SetFrameSync.deserialize(params),
+      'set_semantics': (Map<String, String> params) => new SetSemantics.deserialize(params),
       'scroll': (Map<String, String> params) => new Scroll.deserialize(params),
       'scrollIntoView': (Map<String, String> params) => new ScrollIntoView.deserialize(params),
       'waitFor': (Map<String, String> params) => new WaitFor.deserialize(params),
@@ -271,4 +274,27 @@ class FlutterDriverExtension {
     _frameSync = setFrameSyncCommand.enabled;
     return new SetFrameSyncResult();
   }
+
+  SemanticsHandle _semantics;
+  bool get _semanticsIsEnabled => RendererBinding.instance.pipelineOwner.semanticsOwner != null;
+
+  Future<SetSemanticsResult> _setSemantics(Command command) async {
+    final SetSemantics setSemanticsCommand = command;
+    final bool semanticsWasEnabled = _semanticsIsEnabled;
+    if (setSemanticsCommand.enabled && _semantics == null) {
+      _semantics = RendererBinding.instance.pipelineOwner.ensureSemantics();
+      if (!semanticsWasEnabled) {
+        // wait for the first frame where semantics is enabled.
+        final Completer<Null> completer = new Completer<Null>();
+        SchedulerBinding.instance.addPostFrameCallback((Duration d) {
+          completer.complete();
+        });
+        await completer.future;
+      }
+    } else if (!setSemanticsCommand.enabled && _semantics != null) {
+      _semantics.dispose();
+      _semantics = null;
+    }
+    return new SetSemanticsResult(semanticsWasEnabled != _semanticsIsEnabled);
+  }
 }

packages/flutter_driver/lib/src/message.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:meta/meta.dart';
+
 /// An object sent from the Flutter Driver to a Flutter application to instruct
 /// the application to perform a task.
 abstract class Command {
@@ -20,6 +22,7 @@ abstract class Command {
   String get kind;
 
   /// Serializes this command to parameter name/value pairs.
+  @mustCallSuper
   Map<String, String> serialize() => <String, String>{
     'command': kind,
     'timeout': '${timeout.inMilliseconds}',

packages/flutter_driver/lib/src/semantics.dart

@@ -0,0 +1,43 @@
+// Copyright 2017 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 'message.dart';
+
+/// Enables or disables semantics.
+class SetSemantics extends Command {
+  @override
+  final String kind = 'set_semantics';
+
+  /// Whether semantics should be enabled or disabled.
+  final bool enabled;
+
+  SetSemantics(this.enabled, { Duration timeout }) : super(timeout: timeout);
+
+  /// Deserializes this command from the value generated by [serialize].
+  SetSemantics.deserialize(Map<String, String> params)
+      : this.enabled = params['enabled'].toLowerCase() == 'true',
+        super.deserialize(params);
+
+  @override
+  Map<String, String> serialize() => super.serialize()..addAll(<String, String>{
+    'enabled': '$enabled',
+  });
+}
+
+/// The result of a [SetSemantics] command.
+class SetSemanticsResult extends Result {
+  SetSemanticsResult(this.changedState);
+
+  final bool changedState;
+
+  /// Deserializes this result from JSON.
+  static SetSemanticsResult fromJson(Map<String, dynamic> json) {
+    return new SetSemanticsResult(json['changedState']);
+  }
+
+  @override
+  Map<String, dynamic> toJson() => <String, dynamic>{
+    'changedState': changedState,
+  };
+}