Wrong size of iced widget when the scale factor isn't 1

[fortime]

Compared to the window created by iced_winit, the size of widgets is equal to that of iced_winit multiplied by the scale factor.

After debug and reading the source code, I found that there are two issues:

1. the code handles size incorrectly. Some are treated as physical size and some are treated as logical size in window state. But all size should be treated as logical size.
2. There is no setting destination of wp viewport when window state is created.

I have create a work in progress pr: 118, can you take a look at it?