Update from https://crrev.com/316786

third_party/harfbuzz-ng/src/hb-utf-private.hh

 /*
  * Copyright © 2011,2012,2014  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 11 matching lines @@
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Google Author(s): Behdad Esfahbod
  */
 
 #ifndef HB_UTF_PRIVATE_HH
 #define HB_UTF_PRIVATE_HH
 
 #include "hb-private.hh"
 
-template <typename T, bool validate=true> struct hb_utf_t;
 
+struct hb_utf8_t
+{
+  typedef uint8_t codepoint_t;
 
-/* UTF-8 */
-
-template <>
-struct hb_utf_t<uint8_t, true>
-{
   static inline const uint8_t *
   next (const uint8_t *text,
         const uint8_t *end,
         hb_codepoint_t *unicode,
         hb_codepoint_t replacement)
   {
     /* Written to only accept well-formed sequences.
      * Based on ideas from ICU's U8_NEXT.
      * Generates one "replacement" for each ill-formed byte. */
 
@@ skipping 74 matching lines @@
   }
 
   static inline unsigned int
   strlen (const uint8_t *text)
   {
     return ::strlen ((const char *) text);
   }
 };
 
 
-/* UTF-16 */
+struct hb_utf16_t
+{
+  typedef uint16_t codepoint_t;
 
-template <>
-struct hb_utf_t<uint16_t, true>
-{
   static inline const uint16_t *
   next (const uint16_t *text,
         const uint16_t *end,
         hb_codepoint_t *unicode,
         hb_codepoint_t replacement)
   {
     hb_codepoint_t c = *text++;
 
     if (likely (!hb_in_range (c, 0xD800u, 0xDFFFu)))
     {
@@ skipping 48 matching lines @@
   static inline unsigned int
   strlen (const uint16_t *text)
   {
     unsigned int l = 0;
     while (*text++) l++;
     return l;
   }
 };
 
 
-/* UTF-32 */
+template <bool validate=true>
+struct hb_utf32_t
+{
+  typedef uint32_t codepoint_t;
 
-template <bool validate>
-struct hb_utf_t<uint32_t, validate>
-{
   static inline const uint32_t *
   next (const uint32_t *text,
         const uint32_t *end HB_UNUSED,
         hb_codepoint_t *unicode,
         hb_codepoint_t replacement)
   {
     hb_codepoint_t c = *text++;
     if (validate && unlikely (c > 0x10FFFFu || hb_in_range (c, 0xD800u, 0xDFFFu)))
       goto error;
     *unicode = c;
@@ skipping 17 matching lines @@
   static inline unsigned int
   strlen (const uint32_t *text)
   {
     unsigned int l = 0;
     while (*text++) l++;
     return l;
   }
 };
 
 
+struct hb_latin1_t
+{
+  typedef uint8_t codepoint_t;
+
+  static inline const uint8_t *
+  next (const uint8_t *text,
+        const uint8_t *end HB_UNUSED,
+        hb_codepoint_t *unicode,
+        hb_codepoint_t replacement HB_UNUSED)
+  {
+    *unicode = *text++;
+    return text;
+  }
+
+  static inline const uint8_t *
+  prev (const uint8_t *text,
+        const uint8_t *start HB_UNUSED,
+        hb_codepoint_t *unicode,
+        hb_codepoint_t replacement)
+  {
+    *unicode = *--text;
+    return text;
+  }
+
+  static inline unsigned int
+  strlen (const uint8_t *text)
+  {
+    unsigned int l = 0;
+    while (*text++) l++;
+    return l;
+  }
+};
+
 #endif /* HB_UTF_PRIVATE_HH */