[gtk/a11y/component: 2/4] Add size as a platform acccessible state

[Matthias Clasen <matthiasc src gnome org>]

commit 0b42115666ebbbb8ef7e51050704efe04468d551
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Oct 13 21:18:39 2020 -0400

    Add size as a platform acccessible state
    
    This lets us trigger a change in the AT contexts
    by saying that this platform state changed.

 gtk/gtkaccessible.c       | 3 ++-
 gtk/gtkatcontextprivate.h | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index 1f3e2a3209..36c2781b64 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -677,7 +677,7 @@ gtk_accessible_platform_changed (GtkAccessible               *self,
 /*<private>
  * gtk_accessible_get_platform_state:
  * @self: a #GtkAccessible
- * @state: platform state to query
+ * @state: a boolean platform state to query
  *
  * Query a platform state, such as focus.
  *
@@ -693,6 +693,7 @@ gboolean
 gtk_accessible_get_platform_state (GtkAccessible              *self,
                                    GtkAccessiblePlatformState  state)
 {
+  g_return_val_if_fail (state != GTK_ACCESSIBLE_PLATFORM_STATE_SIZE, FALSE);
   return GTK_ACCESSIBLE_GET_IFACE (self)->get_platform_state (self, state);
 }
 
diff --git a/gtk/gtkatcontextprivate.h b/gtk/gtkatcontextprivate.h
index 4fec1444c8..af32fd206a 100644
--- a/gtk/gtkatcontextprivate.h
+++ b/gtk/gtkatcontextprivate.h
@@ -83,11 +83,13 @@ typedef enum {
 typedef enum {
   GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSABLE,
   GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED,
+  GTK_ACCESSIBLE_PLATFORM_STATE_SIZE,
 } GtkAccessiblePlatformState;
 
 typedef enum {
   GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSABLE = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSABLE,
   GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSED   = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED,
+  GTK_ACCESSIBLE_PLATFORM_CHANGE_SIZE      = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_SIZE,
 } GtkAccessiblePlatformChange;
 
 struct _GtkATContext