[webview_flutter] Added Android implementation of PlatformWebViewController

[mvanbeusekom]

Adds the Android implementation of the PlatformWebViewController 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.

[stuartmorgan-g]

Mostly looks good, but with the caveat that as I mentioned I'm not immersed in this code so I would likely not catch subtle errors (e.g., around the weak handling, or proxying). @bparrishMines should ideally take a look, but if he isn't able to review soon we can land it to unblock the next steps, and he can do a post-landing review for any follow-up since presumably issue would be internal details, not API-level.

[bparrishMines]

LGTM

@stuartmorgan this and other PRs are getting the error:

❗ Failed to stop: Error getting access token for service account: 400 Bad Request
POST https://oauth2.googleapis.com/token
{"error":"invalid_grant","error_description":"Invalid JWT Signature."}, iss: [[email protected]](mailto:[email protected])

Could this be caused by this PR being merge to a branch that isn't main?

[bparrishMines]

It looks like pulling in the latest changes from the main branch into v4_webview fixes these test errors: #6713. Could you review this PR?

[stuartmorgan-g]

That was probably due to a credential rotation.

[bparrishMines]

@mvanbeusekom It looks like this PR still had some failing analysis errors. Can you fix them in your next PR?

Analyzing webview_flutter_android...

   info - lib/src/v4/src/android_webview_controller.dart:17:8 - Unused import: '../../android_webview.dart'. Try removing the import directive. - unused_import
   info - lib/src/v4/src/android_webview_controller.dart:18:8 - Unused import: '../../instance_manager.dart'. Try removing the import directive. - unused_import

[mvanbeusekom]

@mvanbeusekom It looks like this PR still had some failing analysis errors. Can you fix them in your next PR?

Analyzing webview_flutter_android...

   info - lib/src/v4/src/android_webview_controller.dart:17:8 - Unused import: '../../android_webview.dart'. Try removing the import directive. - unused_import
   info - lib/src/v4/src/android_webview_controller.dart:18:8 - Unused import: '../../instance_manager.dart'. Try removing the import directive. - unused_import

Sorry about that, completely missed it. PR #6732 should fix this.