Repository: flutter
Issue: Webview plugin does not support pencil input
Labels: a: text input,platform-ios,a: tablet,a: platform-views,p: webview,package,has reproducible steps,P2,found in release: 3.0,found in release: 3.1,team-ios,triaged-ios

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## Steps to Reproduce

<!-- Please include full steps to reproduce so that we can reproduce the problem. -->

1. Execute `flutter run` on the code sample <!-- (see "Code sample" section below) -->
2. Apple pencil sliding input results cannot be absorbed into the input box.

**Expected results:** <!-- what did you want to see? -->

https://user-images.githubusercontent.com/3472623/177976869-b9d8b894-c27b-4584-b1ff-f90df9d08c77.mp4


**Actual results:** <!-- what did you see? -->

https://user-images.githubusercontent.com/3472623/177976845-e2176878-7936-4c0b-a36b-8fea1f342a53.mp4


<details>
<summary>Code sample</summary>

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```dart
void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: WebView(
        initialUrl: "https://www.bing.com/",
        javascriptMode: JavascriptMode.unrestricted,
        javascriptChannels: {
          JavascriptChannel(
              name: 'Print',
              onMessageReceived: (JavascriptMessage message) {
              })
        },
      ),
    );
  }
}

```

</details>

<details>
  <summary>Logs</summary>

<!--
     Run `flutter analyze` and attach any output of that command below.
     If there are any analysis errors, try resolving them before filing this issue.
-->
pub.yaml
```
dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^1.0.2
  webview_flutter: ^3.0.4

```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
❯ flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.0.4, on macOS 12.4 21F79 darwin-x64, locale
    en-CN)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 13.3)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2020.3)
[✓] IntelliJ IDEA Community Edition (version 2022.1.1)
[✓] VS Code (version 1.68.1)
```

</details>


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