Roll HarfBuzz to 1.4.6

third_party/harfbuzz-ng/src/hb-ot-shape-complex-arabic.cc

 /*
  * Copyright © 2010,2012  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
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
@@ skipping 522 matching lines @@
       /* Number of additional times to repeat each repeating tile. */
       int n_copies = 0;
 
       hb_position_t w_remaining = w_total - w_fixed;
       if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0)
         n_copies = (sign * w_remaining) / (sign * w_repeating) - 1;
 
       /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */
       hb_position_t extra_repeat_overlap = 0;
       hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1);
-      if (shortfall > 0)
+      if (shortfall > 0 && n_repeating > 0)
       {
         ++n_copies;
         hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining;
         if (excess > 0)
           extra_repeat_overlap = excess / (n_copies * n_repeating);
       }
 
       if (step == MEASURE)
       {
         extra_glyphs_needed += n_copies * n_repeating;
@@ skipping 61 matching lines @@
   NULL, /* preprocess_text */
   postprocess_glyphs_arabic,
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */
   setup_masks_arabic,
   NULL, /* disable_otl */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };