Repository: flutter
Issue: System UI overlay doesn't show up as promised when keyboard is enabled
Labels: a: text input,c: regression,e: device-specific,platform-android,engine,d: api docs,a: layout,has reproducible steps,P2,found in release: 2.5,found in release: 2.6,team-android,triaged-android

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## Steps to Reproduce

1. Run `flutter create bug`.
2. replace the main.dart with 
```dart
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await SystemChrome.setEnabledSystemUIOverlays([]);
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',

      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {

      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
            TextField()
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}
```
3. When you click on the input text, 

**Expected results:** <!-- what did you want to see? -->
Android should show the system ui overlays
**Actual results:** <!-- what did you see? -->
Instead it shows a white bar under the keyboard as shown in screen shot
![photo_2021-09-09_15-51-49](https://user-images.githubusercontent.com/445845/132753415-10113b6e-a49f-4310-beec-8b128b9c2f8f.jpg)

<details>
  <summary>Logs</summary>

<!--
      Run your application with `flutter run --verbose` and attach all the
      log output below between the lines with the backticks. If there is an
      exception, please see if the error message includes enough information
      to explain how to solve the issue.
-->

```
[   +4 ms] Flutter run key commands.
[   +3 ms] r Hot reload. 🔥🔥🔥
[   +1 ms] R Hot restart.
[        ] h Repeat this help message.
[        ] d Detach (terminate "flutter run" but leave application running).
[        ] c Clear the screen
[        ] q Quit (terminate the application on the device).
[        ] 💪 Running with sound null safety 💪
[        ] An Observatory debugger and profiler on Pixel 3a XL is available at: http://127.0.0.1:59650/9ApiWogqQT8=/
[ +728 ms] The Flutter DevTools debugger and profiler on Pixel 3a XL is available at: http://127.0.0.1:9102?uri=http%3A%2F%2F127.0.0.1%3A59650%2F9ApiWogqQT8%3D%2F
[+1268 ms] I/eyboard_proble( 6998): Waiting for a blocking GC ProfileSaver
[+63985 ms] W/IInputConnectionWrapper( 6998): beginBatchEdit on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): getTextBeforeCursor on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): getTextAfterCursor on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): getSelectedText on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): endBatchEdit on inactive InputConnection
[  +17 ms] W/IInputConnectionWrapper( 6998): beginBatchEdit on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): endBatchEdit on inactive InputConnection
[   +1 ms] W/IInputConnectionWrapper( 6998): beginBatchEdit on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): endBatchEdit on inactive InputConnection
[  +46 ms] W/IInputConnectionWrapper( 6998): beginBatchEdit on inactive InputConnection
[        ] W/IInputConnectionWrapper( 6998): endBatchEdit on inactive InputConnection
```

<!--
     Run `flutter analyze` and attach any output of that command below.
     If there are any analysis errors, try resolving them before filing this issue.
-->

```
Analyzing keyboard_problem...
No issues found! (ran in 3.8s)

```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel stable, 2.2.3, on macOS 11.3 20E232 darwin-x64, locale en-CA)
    • Flutter version 2.2.3 at /Users/abizanz/tools/flutter
    • Framework revision f4abaa0735 (2 months ago), 2021-07-01 12:46:11 -0700
    • Engine revision 241c87ad80
    • Dart version 2.13.4

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/abizanz/Library/Android/sdk
    • Platform android-30, build-tools 30.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5, Build version 12E262
    • CocoaPods version 1.10.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

[✓] IntelliJ IDEA Ultimate Edition (version 2021.1.3)
    • IntelliJ at /Applications/IntelliJ IDEA.app
    • Flutter plugin version 59.0.3
    • Dart plugin version 211.7727

[✓] VS Code (version 1.60.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.24.0

[✓] Connected device (3 available)
    • Pixel 3a XL (mobile) • 94EAX0DTAC • android-arm64  • Android 11 (API 30)
    • macOS (desktop)      • macos      • darwin-x64     • macOS 11.3 20E232 darwin-x64
    • Chrome (web)         • chrome     • web-javascript • Google Chrome 86.0.4240.183

• No issues found!
```

</details>