gdksurface-win32.c: Disable AeroSnap for surface if not resizable

AeroSnap essentially resizes the surface by all means, so if a surface
is not resizable, just bail out of the operation, even though it is
triggered by a move operation.

This matches what is done in other Windows applications.

gdk/win32/gdksurface-win32.c

@@ -3198,6 +3198,14 @@ handle_aerosnap_move_resize (GdkSurface                   *window,
   int halfright = 0;
   int fullup = 0;
   gboolean fullup_edge = FALSE;
+  GdkWin32Surface *impl = GDK_WIN32_SURFACE (window);
+
+  if (context->op == GDK_WIN32_DRAGOP_MOVE)
+    {
+      if (impl->toplevel_layout != NULL &&
+         !gdk_toplevel_layout_get_resizable (impl->toplevel_layout))
+        return;
+    }
 
   if (context->op == GDK_WIN32_DRAGOP_RESIZE)
     switch (context->edge)