GTK4 doesn't have WS_CHILD windows anymore, so hWndParent argument
to CreateWindowEx() is always interpreted as the owner window,
not the parent window.
A window with an owner:
* is above the owner in Z-order
* is destroyed when the owner is destroyed
* is hidden when the owner is minimized
This is enforced by the OS.
GTK can only allow this for popup windows.
Desktop window must never[0] be an owner.
[0]: https://devblogs.microsoft.com/oldnewthing/20040224-00/?p=40493
On Windows that call resizes the native window immediately,
and the corresponding GDK event is emitted and processed
before the control is returned to gtk_window_move_resize().
Therefore, update freeze and configure_request_count increment
must happen before the call, not after it.
Popups can't be active or inactive, so emitting GDK events
in response to WM_ACTIVATE makes no sense for these kinds
of GDK surfaces.
The jury is still out on whether we should block (return 0)
or ignore (don't return anything) this message.
Blocking WM_NCACTIVATE (which we currently ignore) is definitely
not an option - it completely breaks input somehow.
1) Handle GDK_SURFACE_POPUP in RegisterGdkClass()
(for now pretend it's the same as GDK_SURFACE_TOPLEVEL)
2) Remove useless code from GDK_SURFACE_TOPLEVEL case in _gdk_win32_display_create_surface()
(now there's just GDK_SURFACE_TOPLEVEL there, no need for a type check)
3) Have a separate case for GDK_SURFACE_POPUP and ensure that
it doesn't get WS_CHILDWINDOW (and neither should GDK_SURFACE_TEMP).
We were queuing an allocation whenever
the popover is flipped over, unnecessarily,
since we don't change the size of the surface.
This was showing up as popovers being invisible
when flipped over, under X.
There is no need for popups to connect to the frame
clock to pause and unpause events on the display -
the toplevel already does it.
And don't connect to paint either - handle paint
on popups recursively.
Somewhat change the order of initialization (to be closer
to what Wayland backend does).
Also remove the wrapper field that is no longer needed -
it used to hold a pointer to the main GdkWindow instance,
which wrapped GdkWin32ImplWindow. Since impls are gone,
nothing is wrapping anything anymore.
Fix a substitution error, where wrong pointer was added
to the hash table. Added a comment to ensure that future readers
(including myself) won't be confused by the fact that we're
inserting a pointer instead of the handle itself.
