Summary:
In order to properly implement xdg_surface.set_window_geometry we need
two kinds of geometry - frame and buffer. The frame geometry specifies
visible bounds of the client on the screen, excluding client-side drop
shadows. The buffer geometry specifies rectangle on the screen that the
attached buffer or x11 pixmap occupies on the screen.

This change renames the geometry property to frameGeometry in order to
reflect the new meaning assigned to it as well to make it easier to
differentiate between frame geometry and buffer geometry in the future.

Reviewers: #kwin

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D24334