[gtk+] stylecontext: Handle querying the wrong state better

[Benjamin Otte <otte src gnome org>]

commit a3995d8c86e80d39d6044f3f976c9f6deef1fa05
Author: Benjamin Otte <otte redhat com>
Date:   Tue Oct 21 02:06:46 2014 +0200

    stylecontext: Handle querying the wrong state better
    
    When a getter function (like get_color()) is called and the passed in
    state doesn't match the current state returned via get_state(), we used
    to do a trick: We called save()/set_state() on the context before
    getting the values.
    
    Unfortunately, since 3a337156d11a86c7a88f1f30a09276fdf6f63008 this
    has the unfortunate side effect that it also creates a child element.
    This breaks various old codebases (spinbutton has been fixed in
    998feeb2bc3e37275cfe915e128179d2704ca9c8, Webkit is fixed in
    https://bugs.webkit.org/show_bug.cgi?id=137803 ) unfortunately.
    
    So instead, look up the values manually ensuring that no child element
    is created but the correct state is used.

 gtk/gtkstylecontext.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkstylecontext.c b/gtk/gtkstylecontext.c
index 3752ce3..4cb8348 100644
--- a/gtk/gtkstylecontext.c
+++ b/gtk/gtkstylecontext.c
@@ -738,15 +738,17 @@ static GtkCssComputedValues *
 style_values_lookup_for_state (GtkStyleContext *context,
                                GtkStateFlags    state)
 {
+  GtkCssNodeDeclaration *decl;
   GtkCssComputedValues *values;
 
   if (gtk_css_node_declaration_get_state (context->priv->info->decl) == state)
     return g_object_ref (style_values_lookup (context));
 
-  gtk_style_context_save (context);
-  gtk_style_context_set_state (context, state);
-  values = g_object_ref (style_values_lookup (context));
-  gtk_style_context_restore (context);
+  decl = gtk_css_node_declaration_ref (context->priv->info->decl);
+  gtk_css_node_declaration_set_state (&decl, state);
+  values = _gtk_css_computed_values_new ();
+  build_properties (context, values, decl, NULL);
+  gtk_css_node_declaration_unref (decl);
 
   return values;
 }