tree/view: Do not clip to geometry if using CSD

[thal]

As of commit 9da295c, surfaces of xdg_toplevels are clipped to a region defined by the geometry. This causes drop shadows of floating windows to be cut off, as seen with gnome-calculator against a white background:

This PR will avoid clipping if a sway_view is in a floating container and using CSD.

[rpigott]

I think it should just be using con->current.content_x instead of con->view->geometry.x here.

[thal]

Tried this but it did not work properly. Looks like content_x and content_y are absolute coordinates, while subsurface_tree_set_clip expects surface-local coordinates.

[thal]

The new revision passes con->view->geometry to subsurface_tree_set_clip which is more consistent with the coordinates, and cleans up the code slightly.

[Nefsen402]

I think the only difference between clipping with the geometry size instead of the content_{width, height} size is that if the application decides it shouldn't configure to the size of the window sway wanted. This is a problem when the application is bigger than the frame (this can be easy to trigger if you tile firefox and make it small - it will refuse to configure smaller than a certain size). This will allow firefox to overflow the bounds of the container. I believe we need to keep the content_{width, height} size.

[thal]

I've restored the patch to use content_width, content_height.
@Nefsen402, I tested with Firefox as you suggested, but I did not see any issues with either version of the patch, even when the configured size was smaller than the container.