Handle U+3099/309A Kana Voiced Sound Marks in complex path

Source/platform/fonts/UTF16TextIterator.h

 /*
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 27 matching lines @@
     UTF16TextIterator(const UChar*, int offset, int endOffset, int length);
 
     inline bool consume(UChar32& character)
     {
         if (m_offset >= m_endOffset)
             return false;
 
         character = *m_characters;
         m_currentGlyphLength = 1;
 
-        if (character < hiraganaLetterSmallACharacter || consumeSlowCase(character)) {
+        if (!U16_IS_SURROGATE(character) || consumeSurrogatePair(character)) {
+            // TODO(kojii): This looks broken, we should actually check whether

[drott, 2015/07/17 15:15:58]

Minor: I'd suggest to move this comment to a bug report, e.g. "Check
UTF16TextITerator's category mask behavior" and explain the overlap with
HarfBuzz there. In my opinion, here in the code it does not add much without
knowing the context.

[kojii, 2015/07/17 16:32:58]

Moved to crbug.com/511306, thanks for the advice!

+            // the *next* character is U_GC_M_MASK or not.
+            // Also this is redundant with what HarfBuzzShaper does. Either one
+            // should be removed once the simple path is gone: crbug.com/404597
             if (U_GET_GC_MASK(character) & U_GC_M_MASK)
                 consumeMultipleUChar();
             return true;
         }
 
         return false;
     }
 
     void advance()
     {
         m_characters += m_currentGlyphLength;
         m_offset += m_currentGlyphLength;
     }
 
     int offset() const { return m_offset; }
     const UChar* characters() const { return m_characters; }
     const UChar* glyphEnd() const { return m_characters + m_currentGlyphLength; }
     // FIXME: Only used by SimpleShaper, should be removed once the SimpleShaper
     // is removed.
     unsigned glyphLength() const { return m_currentGlyphLength; }
 
 private:
-    bool consumeSlowCase(UChar32&);
+    bool consumeSurrogatePair(UChar32&);
     void consumeMultipleUChar();
-    UChar32 normalizeVoicingMarks();
 
     const UChar* m_characters;
     const UChar* m_charactersEnd;
     int m_offset;
     int m_endOffset;
     unsigned m_currentGlyphLength;
 };
 
 }
 
 #endif