2158 [video_player] Basic test for VideoPlayerController initialization

2273 [video_player] Add platform interface

2286 [video_player] Improve DartDocs and test coverage

Plugin: Webview Flutter

We upgraded the Webview Flutter plugin to the new plugin API,
and made some bug fixes.

1996 [webview_flutter] Allow underscores anywhere for Javascript Channel name

2257 [webview_flutter] Add async NavigationDelegates

Tooling