Repository: flutter
Issue: [WebView] Flutter webView plugin has no resourceId on web inputs below api 29 with SurfaceAndroidWebView() 
Labels: platform-android,p: webview,package,e: OS-version specific,P2,team-android,triaged-android

Flutter webView plugin has no resourceId on web inputs below api 29 with SurfaceAndroidWebView(). It's ok on api 29 and further.

## Steps to Reproduce

1. Make a widget in the default demo app with webview_flutter: ^1.0.7 wich return a webView Widget : 
```
WebView(
      initialUrl: widget.initialUrl,
      javascriptMode: widget.javascriptMode,
      navigationDelegate: widget.navigationDelegate,
      onWebViewCreated: (controller) {
        _webViewController = controller;
        if (widget.onWebViewCreated != null) {
          widget.onWebViewCreated!(controller);
        }
      },
      gestureNavigationEnabled: widget.gestureNavigationEnabled,
    )
```
2. Display a web page with html inputs which have html ids
3. Observe the view with uiautomatorviewer

**Expected results:** On Android 10 Api 29, you can see resourceIds on html input fields

**Actual results:** On Android 9 Api 28, there are no resourceIds on the fields

```
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    WebView.platform = SurfaceAndroidWebView();
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: SafeArea(
        child: WebView(
          initialUrl:
              'https://connect.sncf.com/login?client_id=ECE_01006_PR1&redirect_uri=https:%2F%2Fmoncompte.sncf.com%2FredirectAuthentication',
          javascriptMode: JavascriptMode.unrestricted,
          gestureNavigationEnabled: true,
        ),
      ),
    );
  }
}
```
![Capture d’écran 2020-12-23 à 12 42 13](https://user-images.githubusercontent.com/8292854/102993035-bef41480-451c-11eb-800f-4a4ecd04a23b.png)

<details>
  <summary>Logs</summary>

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```

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<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel unknown, 1.24.0-10.2.pre, on Mac OS X 10.15.7 19H15 darwin-x64, locale fr-FR)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
[✓] Xcode - develop for iOS and macOS (Xcode 12.1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.0)
[✓] IntelliJ IDEA Ultimate Edition (version 2020.2.3)
[✓] IntelliJ IDEA Ultimate Edition (version 2020.3)
[✓] VS Code (version 1.51.1)
[✓] Connected device (3 available)

• No issues found!
```

</details>