Updated memory_nav_test with FlutterDriver.scrollUntilVisible() (#16009)

examples/flutter_gallery/test_driver/memory_nav_test.dart

-import 'dart:async';
-
 import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart';
 
-const Duration kWaitBetweenActions = const Duration(milliseconds: 250);
-
 void main() {
   group('flutter gallery transitions', () {
     FlutterDriver driver;
@@ -18,21 +14,16 @@ void main() {
     });
 
     test('navigation', () async {
-      final Completer<Null> completer = new Completer<Null>();
-      bool scroll = true;
       final SerializableFinder menuItem = find.text('Text fields');
-      driver.waitFor(menuItem).then<Null>((Null value) async {
-        scroll = false;
-        for (int i = 0; i < 15; i++) {
-          await driver.tap(menuItem);
-          await driver.tap(find.byTooltip('Back'));
-        }
-        completer.complete();
-      });
-      while (scroll) {
-        await driver.scroll(find.text('Flutter Gallery'), 0.0, -500.0, const Duration(milliseconds: 80));
+      await driver.scrollUntilVisible(find.byType('CustomScrollView'), menuItem,
+        dyScroll: -300.0,
+        alignment: 0.5,
+        timeout: const Duration(minutes: 1),
+      );
+      for (int i = 0; i < 15; i++) {
+        await driver.tap(menuItem);
+        await driver.tap(find.byTooltip('Back'));
       }
-      await completer.future;
-    }, timeout: const Timeout(const Duration(minutes: 1)));
+    });
   });
 }

examples/flutter_gallery/test_driver/scroll_perf_test.dart

@@ -22,9 +22,8 @@ void main() {
 
     test('measure', () async {
       final Timeline timeline = await driver.traceAction(() async {
-        // Find the scrollable stock list
-        final SerializableFinder stockList = find.byValueKey('Gallery List');
-        expect(stockList, isNotNull);
+        final SerializableFinder home = find.byValueKey('Gallery List');
+        expect(home, isNotNull);
 
         await driver.tap(find.text('Vignettes'));
         await driver.tap(find.text('Components'));
@@ -34,13 +33,13 @@ void main() {
         // https://github.com/flutter/flutter/issues/3316
         // Scroll down
         for (int i = 0; i < 5; i++) {
-          await driver.scroll(stockList, 0.0, -300.0, const Duration(milliseconds: 300));
+          await driver.scroll(home, 0.0, -300.0, const Duration(milliseconds: 300));
           await new Future<Null>.delayed(const Duration(milliseconds: 500));
         }
 
         // Scroll up
         for (int i = 0; i < 5; i++) {
-          await driver.scroll(stockList, 0.0, 300.0, const Duration(milliseconds: 300));
+          await driver.scroll(home, 0.0, 300.0, const Duration(milliseconds: 300));
           await new Future<Null>.delayed(const Duration(milliseconds: 500));
         }
       });