gtk: Add a copy of some deprecated pango api

We use pango_find_base_dir() in a few places, and
this api has been deprecated.

gtk/gtkpango.c

@@ -25,6 +25,7 @@
 #include "config.h"
 #include "gtkpango.h"
 #include <pango/pangocairo.h>
+#include <fribidi.h>
 #include "gtkintl.h"
 
 #define GTK_TYPE_FILL_LAYOUT_RENDERER            (_gtk_fill_layout_renderer_get_type())
@@ -1321,3 +1322,46 @@ _gtk_pango_attr_list_merge (PangoAttrList *into,
 
   return into;
 }
+
+PangoDirection
+_gtk_pango_unichar_direction (gunichar ch)
+{
+  FriBidiCharType fribidi_ch_type;
+
+  G_STATIC_ASSERT (sizeof (FriBidiChar) == sizeof (gunichar));
+
+  fribidi_ch_type = fribidi_get_bidi_type (ch);
+
+  if (!FRIBIDI_IS_STRONG (fribidi_ch_type))
+    return PANGO_DIRECTION_NEUTRAL;
+  else if (FRIBIDI_IS_RTL (fribidi_ch_type))
+    return PANGO_DIRECTION_RTL;
+  else
+    return PANGO_DIRECTION_LTR;
+}
+
+PangoDirection
+_gtk_pango_find_base_dir (const gchar *text,
+                          gint         length)
+{
+  PangoDirection dir = PANGO_DIRECTION_NEUTRAL;
+  const gchar *p;
+
+  g_return_val_if_fail (text != NULL || length == 0, PANGO_DIRECTION_NEUTRAL);
+
+  p = text;
+  while ((length < 0 || p < text + length) && *p)
+    {
+      gunichar wc = g_utf8_get_char (p);
+
+      dir = _gtk_pango_unichar_direction (wc);
+
+      if (dir != PANGO_DIRECTION_NEUTRAL)
+        break;
+
+      p = g_utf8_next_char (p);
+    }
+
+  return dir;
+}
+

gtk/gtkpango.h

@@ -82,6 +82,9 @@ gchar *_gtk_pango_get_text_after  (PangoLayout     *layout,
 PangoAttrList *_gtk_pango_attr_list_merge (PangoAttrList *into,
                                            PangoAttrList *from);
 
+PangoDirection _gtk_pango_find_base_dir (const gchar *text,
+                                         gint         length);
+
 G_END_DECLS
 
 #endif /* __GTK_PANGO_H__ */