[vte] a11y: Fix omitted first letter when scrolling

[Egmont Koblinger <egmontkob src gnome org>]

commit 3841316afc3df1d216e0eb5f158dc636c585b1ae
Author: Egmont Koblinger <egmont gmail com>
Date:   Sun Aug 3 13:22:15 2014 +0200

    a11y: Fix omitted first letter when scrolling
    
    https://bugzilla.gnome.org/show_bug.cgi?id=657960

 src/vteaccess.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/vteaccess.c b/src/vteaccess.c
index 40a7e3c..9c796a1 100644
--- a/src/vteaccess.c
+++ b/src/vteaccess.c
@@ -609,9 +609,12 @@ vte_terminal_accessible_text_scrolled(VteTerminal *terminal,
                if (inserted) {
                        len = priv->snapshot_text->len;
                        if (len > i) {
+                               /* snapshot_text always contains a trailing '\n',
+                                * insertion happens in front of it: bug 657960 */
+                               g_assert(i >= 1);
                                emit_text_changed_insert(G_OBJECT(accessible),
                                                         priv->snapshot_text->str,
-                                                        i,
+                                                        i - 1,
                                                         len - i);
                        }
                }