* preserve Window callback zones
Run Window callbacks in the zone they are registered in. This is consistent with how other native API work, such as `scheduleMicrotask`, `Timer`, and `dart:io`. This also enables the developers to use the `Zone` API to capture and log unhandled Dart errors.
* refactor wrapping
* new line
* fewer if checks; group getters/setters/fields
* inline _invokeOnPointerDataPacket