Try to make this test less flaky. (#13254)

dev/integration_tests/external_ui/lib/main.dart

@@ -10,6 +10,7 @@ import 'package:flutter_driver/driver_extension.dart';
 
 void main() {
   enableFlutterDriverExtension();
+  debugPrint('Application starting...');
   runApp(new MyApp());
 }
 
@@ -41,6 +42,7 @@ Widget builds: $_widgetBuilds''';
   Future<Null> _nextState() async {
     switch (_state) {
       case FrameState.initial:
+        debugPrint('Starting .5x speed test...');
         _widgetBuilds = 0;
         _summary = 'Producing texture frames at .5x speed...';
         _state = FrameState.slow;
@@ -48,12 +50,14 @@ Widget builds: $_widgetBuilds''';
         channel.invokeMethod('start', _flutterFrameRate ~/ 2);
         break;
       case FrameState.slow:
+        debugPrint('Stopping .5x speed test...');
         await channel.invokeMethod('stop');
         await _summarizeStats();
         _icon = Icons.fast_forward;
         _state = FrameState.afterSlow;
         break;
       case FrameState.afterSlow:
+        debugPrint('Starting 2x speed test...');
         _widgetBuilds = 0;
         _summary = 'Producing texture frames at 2x speed...';
         _state = FrameState.fast;
@@ -61,12 +65,14 @@ Widget builds: $_widgetBuilds''';
         channel.invokeMethod('start', (_flutterFrameRate * 2).toInt());
         break;
       case FrameState.fast:
+        debugPrint('Stopping 2x speed test...');
         await channel.invokeMethod('stop');
         await _summarizeStats();
         _state = FrameState.afterFast;
         _icon = Icons.replay;
         break;
       case FrameState.afterFast:
+        debugPrint('Test complete.');
         _summary = 'Press play to start again';
         _state = FrameState.initial;
         _icon = Icons.play_arrow;
@@ -81,26 +87,34 @@ Widget builds: $_widgetBuilds''';
     _calibrate();
   }
 
+  static const int calibrationTickCount = 600;
+
   /// Measures Flutter's frame rate.
   Future<Null> _calibrate() async {
-    await new Future<Null>.delayed(const Duration(milliseconds: 200));
+    debugPrint('Awaiting calm (3 second pause)...');
+    await new Future<Null>.delayed(const Duration(milliseconds: 3000));
+    debugPrint('Calibrating...');
     DateTime startTime;
     int tickCount = 0;
     Ticker ticker;
-    ticker = createTicker((Duration _) {
+    ticker = createTicker((Duration time) {
-      tickCount++;
+      tickCount += 1;
-      if (tickCount == 120) {
+      if (tickCount == calibrationTickCount) { // about 10 seconds
         final Duration elapsed = new DateTime.now().difference(startTime);
         ticker.stop();
         ticker.dispose();
         setState(() {
           _flutterFrameRate = tickCount * 1000 / elapsed.inMilliseconds;
+          debugPrint('Calibrated: frame rate ${_flutterFrameRate.toStringAsFixed(1)}fps.');
           _summary = '''
 Flutter frame rate is ${_flutterFrameRate.toStringAsFixed(1)}fps.
 Press play to produce texture frames.''';
           _icon = Icons.play_arrow;
           _state = FrameState.initial;
         });
+      } else {
+        if ((tickCount % (calibrationTickCount ~/ 20)) == 0)
+          debugPrint('Calibrating... ${(100.0 * tickCount / calibrationTickCount).floor()}%');
       }
     });
     ticker.start();
@@ -113,7 +127,7 @@ Press play to produce texture frames.''';
 
   @override
   Widget build(BuildContext context) {
-    _widgetBuilds++;
+    _widgetBuilds += 1;
     return new MaterialApp(
       home: new Scaffold(
         body: new Center(

dev/integration_tests/external_ui/test_driver/main_test.dart

@@ -8,7 +8,7 @@ import 'package:test/test.dart';
 
 final RegExp calibrationRegExp = new RegExp('Flutter frame rate is (.*)fps');
 final RegExp statsRegExp = new RegExp('Produced: (.*)fps\nConsumed: (.*)fps\nWidget builds: (.*)');
-const Duration samplingTime = const Duration(seconds: 3);
+const Duration samplingTime = const Duration(seconds: 8);
 
 Future<Null> main() async {
   group('texture suite', () {
@@ -28,7 +28,7 @@ Future<Null> main() async {
       final SerializableFinder summary = find.byValueKey('summary');
 
       // Wait for calibration to complete and fab to appear.
-      await driver.waitFor(fab, timeout: const Duration(seconds: 10));
+      await driver.waitFor(fab, timeout: const Duration(seconds: 40));
 
       final String calibrationResult = await driver.getText(summary);
       final Match matchCalibration = calibrationRegExp.matchAsPrefix(calibrationResult);
@@ -58,7 +58,7 @@ Future<Null> main() async {
       expect(double.parse(matchFast.group(1)), closeTo(flutterFrameRate * 2.0, 5.0));
       expect(double.parse(matchFast.group(2)), closeTo(flutterFrameRate, 10.0));
       expect(int.parse(matchFast.group(3)), 1);
-    });
+    }, timeout: const Timeout(const Duration(minutes: 1)));
 
     tearDownAll(() async {
       driver?.close();