Bug 1600414 Use gdk_window_set_geometry_hints() to set geometry hints, r=jhorak

Use gdk_window_set_geometry_hints() instead of gtk_window_set_geometry_hints() as gdk_*
does not set base sizes which breaks KDE and other window managers.

Differential Revision: https://phabricator.services.mozilla.com/D61552

--HG--
extra : moz-landing-system : lando

widget/gtk/mozgtk/mozgtk.c

@@ -129,6 +129,7 @@ STUB(gdk_window_set_cursor)
 STUB(gdk_window_set_debug_updates)
 STUB(gdk_window_set_decorations)
 STUB(gdk_window_set_events)
+STUB(gdk_window_set_geometry_hints)
 STUB(gdk_window_set_role)
 STUB(gdk_window_set_urgency_hint)
 STUB(gdk_window_set_user_data)
@@ -525,7 +526,6 @@ STUB(gtk_window_set_accept_focus)
 STUB(gtk_window_set_decorated)
 STUB(gtk_window_set_deletable)
 STUB(gtk_window_set_destroy_with_parent)
-STUB(gtk_window_set_geometry_hints)
 STUB(gtk_window_set_icon_name)
 STUB(gtk_window_set_modal)
 STUB(gtk_window_set_skip_taskbar_hint)

widget/gtk/nsWindow.cpp

@@ -1012,7 +1012,10 @@ void nsWindow::ApplySizeConstraints(void) {
       hints |= GDK_HINT_ASPECT;
     }
 
-    gtk_window_set_geometry_hints(GTK_WINDOW(mShell), nullptr, &geometry,
+    // We use gdk_window_set_geometry_hints() instead of
+    // gtk_window_set_geometry_hints() as it sets GDK_HINT_BASE_SIZE
+    // and it breaks KDE and other window managers (Bug 1600414).
+    gdk_window_set_geometry_hints(gtk_widget_get_window(mShell), &geometry,
                                   GdkWindowHints(hints));
   }
 }