Function: handle-switch-frame

Handle a switch-frame event EVENT.
Switch-frame events are usually bound to this function.
A switch-frame event tells Emacs that the window manager has requested
that the user's events be directed to the frame mentioned in the event.
This function selects the selected window of the frame of EVENT.

If EVENT is frame object, handle it as if it were a switch-frame event
to that frame. (fn EVENT)