[webview_flutter] Added Android implementation of PlatformWebViewWidget

[mvanbeusekom]

Adds the Android implementation of the PlatformWebViewWidget to the v4 Android implementation.

Part of issue flutter/flutter#94051

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• [ x] I read and followed the [relevant style guides] and ran [the auto-formatter]. (Unlike the flutter/flutter repo, the flutter/plugins repo does use dart format.)
• I signed the [CLA].
• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• I listed at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy], or this PR is [exempt from version changes].
• I updated CHANGELOG.md to add a description of the change, [following repository CHANGELOG style].
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is [test-exempt].
• All existing and new tests are passing.

[bparrishMines]

I think this still uses VirtualDisplay. This should use the TLHC implementation with PlatformViewLink and PlatformViewsService.initSurfaceAndroidView:
https://github.com/flutter/plugins/blob/main/packages/webview_flutter/webview_flutter_android/lib/webview_surface_android.dart#L47

[bparrishMines]

LGTM with a nit.

It looks like the analyze check is still failing for packages/webview_flutter/webview_flutter_android/lib/src/v4/src/android_webview_controller.dart. It took me a few tries to figure it out since you have to make it work with the current Flutter version and the 2 previous stable versions.

This combination might work:

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';

And remove foundation and gestures.

[bparrishMines]

I debugged the error from the legacy analyze test and it looks like this is the culprit. Updating this version also requires you to update the minimum Flutter version of webview_flutter to 3.3.0.