Repository: flutter
Issue: Stylus doesn't trigger PointerDownEvent
Labels: e: device-specific,platform-android,framework,f: gestures,P2,found in release: 1.20,team-android,triaged-android

## The main problem
When you use a stylus as an input device, sometimes a PointerDownEvent gets triggered and then for the next 5-30sec the application doesn't handle any pointer inputs(it probably just freezes). Then I get a notice from the system that the app isn't responding and in that moment everything works as it should. The Problem then only reoccurs after you restart the Application.

Note: As long as I don't use the stylus everything works fine.

The main strange thing about this is that it only happens sometimes.

## The second problem
When I press the button on my SPen and then touch the display, no pointer down events are triggered at all.

## Steps to Reproduce

1. Create a new Flutter Project and paste the content of the test application into main.dart (https://pastebin.com/PDuDVFQU)
2. Load the application onto your test device
3. Run the app (It seems to me, that this problem occurs with a higher probability if the data of the app is deleted beforehand, and the app is started from the device itself)



Target Platform: Android
Target OS version: 9 
Devices: Samsung tab S4 (SM T830); Samsung Tab S3 (SM T820)

It seems like the problem occurs more frequently on the S4. But this could also be my imagination.


## Logs

Log file: https://pastebin.com/9GFaVMUq
In line 1278 it says I didn't do anything for 20711 ms even though I instantly put the pen down again after I lifted it.

Flutter analyze doesn't return any issues (after you remove the curly brackets in the Strings which don't affect the problem)

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
[✓] Flutter (Channel beta, v1.10.7, on Linux, locale en_US.UTF-8)
    • Flutter version 1.10.7 at
      /home/ich/programming-libraries/flutter-sdk/flutter
    • Framework revision e70236e36c (2 weeks ago), 2019-10-02 09:32:30 -0700
    • Engine revision 9e6314d348
    • Dart version 2.6.0 (build 2.6.0-dev.4.0 1103600280)

 
[!] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at /home/ich/Android/Sdk
    • Android NDK location not configured (optional; useful for native profiling
      support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at:
      /home/ich/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/191.59002
      03/jre/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)
    ! Some Android licenses not accepted.  To resolve this, run: flutter doctor
      --android-licenses

[!] Android Studio (version 3.5)
    • Android Studio at
      /home/ich/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/191.59002
      03
    ✗ 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_202-release-1483-b49-5587405)

[!] VS Code (version 1.39.1)
    • VS Code at /usr/share/code
    ✗ Flutter extension not installed; install from
      https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected device (1 available)
    • SM T830                   • ce11182b6346556a1c7e • android-arm64 • Android
      9 (API 28)


! Doctor found issues in 3 categories.
```

Note: The doctor is wrong. I don't use VSCode and AndroidStudio is up to date with version 3.5.1


Thanks in advance for your help.
- Rimaito