Repository: flutter
Issue: [Android] Add ability to use a theme for splash screen in addition to launch screen
Labels: c: new feature,framework,f: material design,a: quality,c: proposal,a: layout,team-design,triaged-design

I've followed the [documentation](https://flutter.dev/docs/development/ui/advanced/splash-screen) on how to create a launch and splash screen in Android and came up with [this example](https://github.com/Pavel-Sulimau/flutter_android_splash_screen_theming), but it's not so clear to me **how I can make the splash screen look like exactly the same as launch screen** without modifying the normal theme which affects the app itself.


## Steps to Reproduce

<!-- You must include full steps to reproduce so that we can reproduce the problem. -->

1. Grab [this small example](https://github.com/Pavel-Sulimau/flutter_android_splash_screen_theming) with colored screens.
2. Run it (launch screen is red, splash screen is green, app is blue) and pay attention to the status bar.
<img src="https://user-images.githubusercontent.com/8143332/96117479-d4ccd400-0ef2-11eb-82f6-26ed73e4fd86.gif" width="375" height="667" />

**Expected results:**
Ability to apply `LaunchTheme` to splash screen as well, i.e. be able to show splash screen with `windowFullscreen` on, but the flutter app itself without `windowFullscreen`.

**Actual results:**
The splash screen has a status bar.

I've also found some info in the [stackoverflow question](https://stackoverflow.com/questions/55139079/how-to-let-splash-page-full-screen-in-flutter) and in the [medium article](https://medium.com/@diegoveloper/flutter-splash-screen-9f4e05542548), but haven't managed to get it working the way I need.

<details>
  <summary>Logs</summary>

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
flutter doctor -v
[✓] Flutter (Channel beta, 1.22.1, on Mac OS X 10.15.7 19H2, locale en)
    • Flutter version 1.22.1 at /Users/pavel_sulimau/src/open_source/flutter
    • Framework revision f30b7f4db9 (7 days ago), 2020-10-08 10:06:30 -0700
    • Engine revision 75bef9f6c8
    • Dart version 2.10.1

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at /Users/pavel_sulimau/Library/Android/sdk
    • Platform android-30, build-tools 30.0.2
    • 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-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.0.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.0.1, Build version 12A7300
    • CocoaPods version 1.10.0.rc.1

[!] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.50.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.15.0

 
[✓] Connected device (1 available)            
    • sdk gphone x86 arm (mobile) • emulator-5554 • android-x86 • Android 11 (API 30) (emulator)
```

</details>