Revert "Always evaluate the finder in `driver.waitFor*()`" (#11451)

* Revert "Make plugins add their repos to projects in the consuming app (#11447)"

This reverts commit abe1e252.

* Revert "Support for custom build types on Android (#11354)"

This reverts commit 87eec719.

* Revert "add a profile() method (#11443)"

This reverts commit 561d17a8.

* Revert "Fix documentation based on dartdoc's warnings (#11428)"

This reverts commit 6655074b.

* Revert "Improve some docs around WillPopScope. (#11429)"

This reverts commit 58a28a29.

* Revert "temporarily disable broken driver test in integration_ui (#11440)"

This reverts commit 764515ec.

* Revert "style fix"

This reverts commit 00bfc866.

* Revert "tests for waitFor/waitForAbsent"

This reverts commit 31d2ee9c.

* Revert "Always evaluate the finder in `driver.waitFor()` and `driver.waitForAbsent()`"

This reverts commit 11d7c79b.

dev/integration_tests/ui/lib/driver.dart

-// 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/material.dart';
-import 'package:flutter/widgets.dart';
-import 'package:flutter_driver/driver_extension.dart';
-
-void main() {
-  enableFlutterDriverExtension();
-  runApp(new DriverTestApp());
-}
-
-class DriverTestApp extends StatefulWidget {
-  @override
-  State<StatefulWidget> createState() {
-    return new DriverTestAppState();
-  }
-}
-
-class DriverTestAppState extends State<DriverTestApp> {
-  bool present = true;
-
-  @override
-  Widget build(BuildContext context) {
-    return new MaterialApp(
-      home: new Scaffold(
-        appBar: new AppBar(
-          title: const Text('FlutterDriver test'),
-        ),
-        body: new ListView(
-          padding: const EdgeInsets.all(5.0),
-          children: <Widget>[
-            new Row(
-              children: <Widget>[
-                new Expanded(
-                  child: new Text(present ? 'present' : 'absent'),
-                ),
-                new RaisedButton(
-                  child: const Text(
-                    'toggle',
-                    key: const ValueKey<String>('togglePresent'),
-                  ),
-                  onPressed: () {
-                    setState(() {
-                      present = !present;
-                    });
-                  },
-                ),
-              ],
-            ),
-          ],
-        ),
-      ),
-    );
-  }
-}

dev/integration_tests/ui/test_driver/driver_test.dart

-// 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 'package:flutter_driver/flutter_driver.dart';
-import 'package:test/test.dart';
-
-void main() {
-  group('FlutterDriver', () {
-    final SerializableFinder presentText = find.text('present');
-    FlutterDriver driver;
-
-    setUpAll(() async {
-      driver = await FlutterDriver.connect();
-    });
-
-    tearDownAll(() async {
-      await driver.close();
-    });
-
-    test('waitFor should find text "present"', () async {
-      await driver.waitFor(presentText);
-    });
-
-    test('waitForAbsent should time out waiting for text "present" to disappear', () async {
-      try {
-        await driver.waitForAbsent(presentText, timeout: const Duration(seconds: 1));
-        fail('expected DriverError');
-      } on DriverError catch (error) {
-        expect(error.message, contains('Timeout while executing waitForAbsent'));
-      }
-    });
-
-    test('waitForAbsent should resolve when text "present" disappears', () async {
-      // Begin waiting for it to disappear
-      final Completer<Null> whenWaitForAbsentResolves = new Completer<Null>();
-      driver.waitForAbsent(presentText).then(
-        whenWaitForAbsentResolves.complete,
-        onError: whenWaitForAbsentResolves.completeError,
-      );
-
-      // Wait 1 second then make it disappear
-      await new Future<Null>.delayed(const Duration(seconds: 1));
-      await driver.tap(find.byValueKey('togglePresent'));
-
-      // Ensure waitForAbsent resolves
-      await whenWaitForAbsentResolves.future;
-    });
-
-    test('waitFor times out waiting for "present" to reappear', () async {
-      try {
-        await driver.waitFor(presentText, timeout: const Duration(seconds: 1));
-        fail('expected DriverError');
-      } on DriverError catch (error) {
-        expect(error.message, contains('Timeout while executing waitFor'));
-      }
-    });
-
-    test('waitFor should resolve when text "present" reappears', () async {
-      // Begin waiting for it to reappear
-      final Completer<Null> whenWaitForResolves = new Completer<Null>();
-      driver.waitFor(presentText).then(
-        whenWaitForResolves.complete,
-        onError: whenWaitForResolves.completeError,
-      );
-
-      // Wait 1 second then make it appear
-      await new Future<Null>.delayed(const Duration(seconds: 1));
-      await driver.tap(find.byValueKey('togglePresent'));
-
-      // Ensure waitFor resolves
-      await whenWaitForResolves.future;
-    });
-
-    test('waitForAbsent resolves immediately when the element does not exist', () async {
-      await driver.waitForAbsent(find.text('that does not exist'));
-    });
-  });
-}

packages/flutter_driver/lib/src/extension.dart

@@ -200,7 +200,7 @@ class FlutterDriverExtension {
     if (_frameSync)
       await _waitUntilFrame(() => SchedulerBinding.instance.transientCallbackCount == 0);
 
-    await _waitUntilFrame(() => finder.evaluate().isNotEmpty);
+    await _waitUntilFrame(() => finder.precache());
 
     if (_frameSync)
       await _waitUntilFrame(() => SchedulerBinding.instance.transientCallbackCount == 0);
@@ -213,7 +213,7 @@ class FlutterDriverExtension {
     if (_frameSync)
       await _waitUntilFrame(() => SchedulerBinding.instance.transientCallbackCount == 0);
 
-    await _waitUntilFrame(() => finder.evaluate().isEmpty);
+    await _waitUntilFrame(() => !finder.precache());
 
     if (_frameSync)
       await _waitUntilFrame(() => SchedulerBinding.instance.transientCallbackCount == 0);
@@ -268,8 +268,10 @@ class FlutterDriverExtension {
 
   Future<WaitForResult> _waitFor(Command command) async {
     final WaitFor waitForCommand = command;
-    await _waitForElement(_createFinder(waitForCommand.finder));
+    if ((await _waitForElement(_createFinder(waitForCommand.finder))).evaluate().isNotEmpty)
       return new WaitForResult();
+    else
+      return null;
   }
 
   Future<WaitForAbsentResult> _waitForAbsent(Command command) async {