[gtk/matthiasc/a11y] text: Set the readonly accessible property

[Matthias Clasen <matthiasc src gnome org>]

commit efebc3e9a94fd0c0093b01fe161e2e3b0096b504
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Oct 11 23:34:36 2020 -0400

    text: Set the readonly accessible property
    
    This mirrors what we already do for GtkTextView.

 gtk/gtktext.c | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/gtk/gtktext.c b/gtk/gtktext.c
index 6910aeff8b..e57836ee10 100644
--- a/gtk/gtktext.c
+++ b/gtk/gtktext.c
@@ -1482,6 +1482,7 @@ gtk_text_class_init (GtkTextClass *class)
                                        "text.redo", NULL);
 
   gtk_widget_class_set_css_name (widget_class, I_("text"));
+  gtk_widget_class_set_accessible_role (widget_class, GTK_ACCESSIBLE_ROLE_TEXT_BOX);
 }
 
 static void
@@ -5430,6 +5431,10 @@ gtk_text_set_editable (GtkText  *self,
       gtk_text_update_clipboard_actions (self);
       gtk_text_update_emoji_action (self);
 
+      gtk_accessible_update_property (GTK_ACCESSIBLE (self),
+                                      GTK_ACCESSIBLE_PROPERTY_READ_ONLY, !priv->editable,
+                                      -1);
+
       g_object_notify (G_OBJECT (self), "editable");
     }
 }