[web] Platform views reset the 'cursor' set by the glasspane of the app. #72037
Description
Steps to Reproduce
The current implementation of platform views in the web engine introduce a very aggressive reset CSS stylesheet while in DOM-rendering mode:
This causes that changes to the cursor made by the flutter app (through the glass-pane) get reset once the mouse enters a platform view in the app (it seems to revert to cursor: default).
The fix is to inherit the cursor from the outside, after resetting all properties, with cursor: inherit;.
This happens currently near the tip of master:
$ flutter doctor -v
[✓] Flutter (Channel master, 1.24.0-8.0.pre.356, on Linux, locale en_US.UTF-8)
• Flutter version 1.24.0-8.0.pre.356 at /usr/local/google/home/dit/github/flutter
• Framework revision e6bd95bc5c (2 weeks ago), 2020-11-23 14:10:58 -0800
• Engine revision 23a8e027db
• Dart version 2.12.0 (build 2.12.0-62.0.dev)