Update harfbuzz-ng to 0.9.27

third_party/harfbuzz-ng/src/hb-buffer.cc

 /*
  * Copyright © 1998-2004  David Turner and Werner Lemberg
  * Copyright © 2004,2007,2009,2010  Red Hat, Inc.
  * Copyright © 2011,2012  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
@@ skipping 1132 matching lines @@
   /* Wipe the new space */
   if (length > buffer->len) {
     memset (buffer->info + buffer->len, 0, sizeof (buffer->info[0]) * (length - buffer->len));
     if (buffer->have_positions)
       memset (buffer->pos + buffer->len, 0, sizeof (buffer->pos[0]) * (length - buffer->len));
   }
 
   buffer->len = length;
 
   if (!length)
+  {
+    buffer->content_type = HB_BUFFER_CONTENT_TYPE_INVALID;
     buffer->clear_context (0);
+  }
   buffer->clear_context (1);
 
   return true;
 }
 
 /**
  * hb_buffer_get_length:
  * @buffer: a buffer.
  *
  * Returns the number of items in the buffer.
@@ skipping 325 matching lines @@
 
   unsigned int start = 0;
   unsigned int end;
   for (end = start + 1; end < count; end++)
     if (info[start].cluster != info[end].cluster) {
       normalize_glyphs_cluster (buffer, start, end, backward);
       start = end;
     }
   normalize_glyphs_cluster (buffer, start, end, backward);
 }