Revert "Zero marks by GDEF for Tibetan"

This reverts commit d5bd0590ae.

The reasoning behind that logic was flawed and made under
a misunderstanding of the original problem, and caused
regressions as reported by Jonathan Kew in thread titled
"tibetan marks" in Oct 2013.  Apparently I have had fixed
the original problem with this commit:

  7e08f1258d

So, revert the faulty commit and everything seems to be in good
shape.

src/hb-ot-layout-gsubgpos-private.hh

@@ -616,8 +616,8 @@ struct hb_apply_context_t
   }
 
   inline void _set_glyph_props (hb_codepoint_t glyph_index,
-				unsigned int class_guess = 0,
-				bool ligature = false) const
+			  unsigned int class_guess = 0,
+			  bool ligature = false) const
   {
     unsigned int add_in = _hb_glyph_info_get_glyph_props (&buffer->cur()) &
 			  HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE;

src/hb-ot-shape-complex-arabic.cc

@@ -177,6 +177,8 @@ collect_features_arabic (hb_ot_shape_planner_t *plan)
    *
    * This also makes Arial Bold in Windows7 work.  See:
    * https://bugzilla.mozilla.org/show_bug.cgi?id=644184
+   *
+   * TODO: Add test cases for these two.
    */
 
   map->add_gsub_pause (nuke_joiners);
@@ -355,12 +357,6 @@ retry:
   arabic_fallback_plan_shape (fallback_plan, font, buffer);
 }
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_arabic (const hb_segment_properties_t *props HB_UNUSED)
-{
-  return HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE;
-}
-
 
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
 {
@@ -374,6 +370,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
   NULL, /* decompose */
   NULL, /* compose */
   setup_masks_arabic,
-  zero_width_marks_preference_arabic,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };

src/hb-ot-shape-complex-default.cc

@@ -203,21 +203,6 @@ compose_default (const hb_ot_shape_normalize_context_t *c,
   return found;
 }
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_default (const hb_segment_properties_t *props)
-{
-  switch ((hb_tag_t) props->script)
-  {
-    /* Unicode-2.0 additions */
-    case HB_SCRIPT_TIBETAN:
-      return HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE;
-
-    default:
-      return HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE;
-  }
-}
-
-
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
 {
   "default",
@@ -230,6 +215,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
   NULL, /* decompose */
   compose_default,
   NULL, /* setup_masks */
-  zero_width_marks_preference_default,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE,
   true, /* fallback_position */
 };

src/hb-ot-shape-complex-indic.cc

@@ -1797,12 +1797,6 @@ compose_indic (const hb_ot_shape_normalize_context_t *c,
   return c->unicode->compose (a, b, ab);
 }
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_indic (const hb_segment_properties_t *props HB_UNUSED)
-{
-  return HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE;
-}
-
 
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
 {
@@ -1816,6 +1810,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
   decompose_indic,
   compose_indic,
   setup_masks_indic,
-  zero_width_marks_preference_indic,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };

src/hb-ot-shape-complex-myanmar.cc

@@ -263,12 +263,6 @@ set_myanmar_properties (hb_glyph_info_t &info)
 
 
 
-static hb_ot_shape_normalization_mode_t
-normalization_preference_myanmar (const hb_segment_properties_t *props HB_UNUSED)
-{
-  return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT;
-}
-
 static void
 setup_masks_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,
 		   hb_buffer_t              *buffer,
@@ -525,10 +519,11 @@ final_reordering (const hb_ot_shape_plan_t *plan,
   HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position);
 }
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_myanmar (const hb_segment_properties_t *props HB_UNUSED)
+
+static hb_ot_shape_normalization_mode_t
+normalization_preference_myanmar (const hb_segment_properties_t *props HB_UNUSED)
 {
-  return HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY;
+  return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT;
 }
 
 
@@ -544,6 +539,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar =
   NULL, /* decompose */
   NULL, /* compose */
   setup_masks_myanmar,
-  zero_width_marks_preference_myanmar,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
   false, /* fallback_position */
 };

src/hb-ot-shape-complex-private.hh

@@ -39,7 +39,7 @@
 #define complex_var_u8_1()	var2.u8[3]
 
 
-enum hb_ot_shape_zero_width_marks_t {
+enum hb_ot_shape_zero_width_marks_type_t {
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
 //  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_EARLY,
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE,
@@ -140,11 +140,7 @@ struct hb_ot_complex_shaper_t
 		       hb_buffer_t              *buffer,
 		       hb_font_t                *font);
 
-  /* zero_width_marks_preference()
-   * Called during shape().
-   */
-  hb_ot_shape_zero_width_marks_t
-  (*zero_width_marks_preference) (const hb_segment_properties_t *props);
+  hb_ot_shape_zero_width_marks_type_t zero_width_marks;
 
   bool fallback_position;
 };

src/hb-ot-shape-complex-sea.cc

@@ -162,12 +162,6 @@ set_sea_properties (hb_glyph_info_t &info)
 }
 
 
-static hb_ot_shape_normalization_mode_t
-normalization_preference_sea (const hb_segment_properties_t *props HB_UNUSED)
-{
-  return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT;
-}
-
 static void
 setup_masks_sea (const hb_ot_shape_plan_t *plan HB_UNUSED,
 		 hb_buffer_t              *buffer,
@@ -366,10 +360,10 @@ final_reordering (const hb_ot_shape_plan_t *plan,
 }
 
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_sea (const hb_segment_properties_t *props HB_UNUSED)
+static hb_ot_shape_normalization_mode_t
+normalization_preference_sea (const hb_segment_properties_t *props HB_UNUSED)
 {
-  return HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE;
+  return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT;
 }
 
 
@@ -385,6 +379,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_sea =
   NULL, /* decompose */
   NULL, /* compose */
   setup_masks_sea,
-  zero_width_marks_preference_sea,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };

src/hb-ot-shape-complex-thai.cc

@@ -361,13 +361,6 @@ preprocess_text_thai (const hb_ot_shape_plan_t *plan,
     do_thai_pua_shaping (plan, buffer, font);
 }
 
-static hb_ot_shape_zero_width_marks_t
-zero_width_marks_preference_thai (const hb_segment_properties_t *props HB_UNUSED)
-{
-  return HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE;
-}
-
-
 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
 {
   "thai",
@@ -380,6 +373,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
   NULL, /* decompose */
   NULL, /* compose */
   NULL, /* setup_masks */
-  zero_width_marks_preference_thai,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE,
   false,/* fallback_position */
 };

src/hb-ot-shape.cc

@@ -452,7 +452,7 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
   bool ret = false;
   unsigned int count = c->buffer->len;
 
-  switch (c->plan->shaper->zero_width_marks_preference (&c->plan->props))
+  switch (c->plan->shaper->zero_width_marks)
   {
     case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY:
       zero_mark_widths_by_gdef (c->buffer);
@@ -497,7 +497,7 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
     ret = true;
   }
 
-  switch (c->plan->shaper->zero_width_marks_preference (&c->plan->props))
+  switch (c->plan->shaper->zero_width_marks)
   {
     case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE:
       zero_mark_widths_by_unicode (c->buffer);