Summary: In certain circumstances webview rendering is slow because it has to integrate with the android rendering API incase an app wishes to synchronize some App UI with web UI.

This isn't a limitation in chrome itself, which means chrome rendering has better performance for these specific operations (animations mostly).

Personally I think the chrome rendering path should always be used, and apps which want to draw under/over web content will have to deal with a frame or two of delay.

It's amazing bugs like this persist, even with the significant resources of several megacorps allocating legions of full-time developers to the codebase.

To save you having to read a really long comment thread: https://engineering.fb.com/2022/09/30/android/launching-a-ne...

Basically, FB's engineering replaced it with a full chromium based webview and explained the reasons android webview sucks ass.

unfortunately nobody cares :(