gdk backend dependencies in gtk

["Matthias Clasen" <matthiasc poet de>]

Before starting on completing the gdk X backend api docs,  I decided
to take a look at why one would need to access the backend at all.
Here is a list of all the not-gdk-backend-independent widgets (judging
by #include "x11/gdkx.h") I found:

gtkclipboard
gtkcolorsel
gtkplug
gtksocket
gtkselection
gtktreeview
gtkwindow

gtkplug/gtksocket are completely X specific, not much we can do here.
gtkcolorsel/gtktreeview/gtkwindow seem to work just fine without the gdk
backend includes.
gtkselection needs gdk_window_lookup
gtkclipboard needs a way to get a current timestamp:
gdk_x11_get_server_time/GetMessageTime

Is it ok if I remove the gdk backend includes from gtkcolorsel, gtktreeview
and gtkwindow ?

Furthermore, I would propose to add

GdkWindow *gdk_window_lookup (GdkNativeWindow *)

guint gdk_get_current_timestamp (GdkWindow *)

to the gdk frontend in order to remove the backend dependencies from
gtkclipboard and gtkselection.

Comments ?

Matthias