[gtk+] GtkTextHandle: Look up for the first child of a scrolled window found

[Carlos Garnacho <carlosg src gnome org>]

commit 60d7f4376ea5ff1722cd20aced72c167372d2a38
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Feb 24 17:19:48 2016 +0100

    GtkTextHandle: Look up for the first child of a scrolled window found
    
    Text handles use to connect to the first GtkScrollable up the hierarchy
    so they can be repositioned when scrolling. It makes more sense to look
    up the first child of a GtkScrolledWindow, it must be an scrollable too,
    and will be the scrollable that can actually change the position of the
    text handles.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=761676

 gtk/gtktexthandle.c |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktexthandle.c b/gtk/gtktexthandle.c
index 5ed6ebc..cc98d22 100644
--- a/gtk/gtktexthandle.c
+++ b/gtk/gtktexthandle.c
@@ -544,6 +544,21 @@ _gtk_text_handle_update_scrollable (GtkTextHandle *handle,
                         handle);
 }
 
+static GtkWidget *
+gtk_text_handle_lookup_scrollable (GtkTextHandle *handle)
+{
+  GtkTextHandlePrivate *priv;
+  GtkWidget *scrolled_window;
+
+  priv = handle->priv;
+  scrolled_window = gtk_widget_get_ancestor (priv->parent,
+                                             GTK_TYPE_SCROLLED_WINDOW);
+  if (!scrolled_window)
+    return NULL;
+
+  return gtk_bin_get_child (GTK_BIN (scrolled_window));
+}
+
 static void
 _gtk_text_handle_parent_hierarchy_changed (GtkWidget     *widget,
                                            GtkWindow     *previous_toplevel,
@@ -574,7 +589,7 @@ _gtk_text_handle_parent_hierarchy_changed (GtkWidget     *widget,
         }
     }
 
-  scrollable = gtk_widget_get_ancestor (widget, GTK_TYPE_SCROLLABLE);
+  scrollable = gtk_text_handle_lookup_scrollable (handle);
   _gtk_text_handle_update_scrollable (handle, GTK_SCROLLABLE (scrollable));
 }
 
@@ -603,7 +618,7 @@ _gtk_text_handle_set_parent (GtkTextHandle *handle,
                           G_CALLBACK (_gtk_text_handle_parent_hierarchy_changed),
                           handle);
 
-      scrollable = gtk_widget_get_ancestor (parent, GTK_TYPE_SCROLLABLE);
+      scrollable = gtk_text_handle_lookup_scrollable (handle);
     }
 
   _gtk_text_handle_update_scrollable (handle, GTK_SCROLLABLE (scrollable));