a11y: Mark more containers as structural elements

Widgets that just provide grouping and layout to other widgets should
not be relevant to the accessible tree.

gtk/gtkaspectframe.c

@@ -176,6 +176,7 @@ gtk_aspect_frame_class_init (GtkAspectFrameClass *class)
                                                         GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));
 
   gtk_widget_class_set_css_name (GTK_WIDGET_CLASS (class), I_("aspectframe"));
+  gtk_widget_class_set_accessible_role (GTK_WIDGET_CLASS (class), GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void

gtk/gtkbox.c

@@ -278,6 +278,7 @@ gtk_box_class_init (GtkBoxClass *class)
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BOX_LAYOUT);
   gtk_widget_class_set_css_name (widget_class, I_("box"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 static void
 gtk_box_init (GtkBox *box)

gtk/gtkcenterbox.c

@@ -210,6 +210,7 @@ gtk_center_box_class_init (GtkCenterBoxClass *klass)
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CENTER_LAYOUT);
   gtk_widget_class_set_css_name (widget_class, I_("box"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void

gtk/gtkgrid.c

@@ -395,8 +395,8 @@ gtk_grid_class_init (GtkGridClass *class)
   g_object_class_install_properties (object_class, N_PROPERTIES, obj_properties);
 
   gtk_widget_class_set_css_name (widget_class, I_("grid"));
-
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_GRID_LAYOUT);
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static GtkBuildableIface *parent_buildable_iface;

gtk/gtkheaderbar.c

@@ -600,6 +600,7 @@ gtk_header_bar_class_init (GtkHeaderBarClass *class)
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BIN_LAYOUT);
   gtk_widget_class_set_css_name (widget_class, I_("headerbar"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void

gtk/gtkscrolledwindow.c

@@ -868,6 +868,7 @@ gtk_scrolled_window_class_init (GtkScrolledWindowClass *class)
   add_tab_bindings (widget_class, GDK_CONTROL_MASK | GDK_SHIFT_MASK, GTK_DIR_TAB_BACKWARD);
 
   gtk_widget_class_set_css_name (widget_class, I_("scrolledwindow"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static gboolean

gtk/gtkviewport.c

@@ -382,6 +382,7 @@ gtk_viewport_class_init (GtkViewportClass *class)
                                                         GTK_PARAM_READWRITE));
 
   gtk_widget_class_set_css_name (widget_class, I_("viewport"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void

gtk/gtkwindowcontrols.c

@@ -538,6 +538,7 @@ gtk_window_controls_class_init (GtkWindowControlsClass *klass)
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BOX_LAYOUT);
   gtk_widget_class_set_css_name (widget_class, I_("windowcontrols"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void

gtk/gtkwindowhandle.c

@@ -550,6 +550,7 @@ gtk_window_handle_class_init (GtkWindowHandleClass *klass)
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BIN_LAYOUT);
   gtk_widget_class_set_css_name (widget_class, I_("windowhandle"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_GROUP);
 }
 
 static void