[gtk/matthiasc/atspi-child] a11y: Don't present HIDDEN accessibles

[Matthias Clasen <matthiasc src gnome org>]

commit 374a451eeb6e8791fd131862082e742143579b63
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Oct 24 10:32:24 2020 -0400

    a11y: Don't present HIDDEN accessibles
    
    The ARIA spec is clear on this: when an element has the
    HIDDEN state, it should not be presented in the accessible
    tree.
    
    This change is incomplete, we also need to emit child-added/
    removed signals when the state changes, but that needs to
    wait for the child added infrastructure to land.

 gtk/gtkaccessible.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index 49fea56fb6..12be6332a3 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -742,6 +742,8 @@ gtk_accessible_bounds_changed (GtkAccessible *self)
 gboolean
 gtk_accessible_should_present (GtkAccessible *self)
 {
+  GtkATContext *context;
+
   if (GTK_IS_WIDGET (self) &&
       !gtk_widget_get_visible (GTK_WIDGET (self)))
     return FALSE;
@@ -749,6 +751,16 @@ gtk_accessible_should_present (GtkAccessible *self)
   if (gtk_accessible_get_accessible_role (self) == GTK_ACCESSIBLE_ROLE_NONE)
     return FALSE;
 
+  context = gtk_accessible_get_at_context (self);
+  if (gtk_at_context_has_accessible_state (context, GTK_ACCESSIBLE_STATE_HIDDEN))
+    {
+      GtkAccessibleValue *value;
+
+      value = gtk_at_context_get_accessible_state (context, GTK_ACCESSIBLE_STATE_HIDDEN);
+      if (gtk_boolean_accessible_value_get (value))
+        return FALSE;
+    }
+
   return TRUE;
 }