In current PlatformView clipping behavior, clipPath is not completely accurate when the path is a conic path. For example conicTo

Quartz doesn't support conic path. We currently uses quad to approximate conic. This is inaccurate when the weight value is far away from 1. eg. weight = 0.1 or weight = 2.

We need to find a better way to approximate conic path using quartz.

To reproduce:

1. Add a clipPath with conic path widget on top of any PlatformView widget, with a large weight (e.g. weight = 2)
2. Add the same clipPath to a container widget that has the same size with the PlatformView widget.
3. See the visual difference.