Elements whose contents start with an astral Unicode symbol disappear when CSS `::first-letter` is …

Source/platform/text/TextBreakIterator.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007-2009 Torch Mobile, Inc.
  * Copyright (C) 2011 Google Inc. 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.
@@ skipping 32 matching lines @@
     NonSharedCharacterBreakIterator it(string);
     if (!it)
         return stringLength;
 
     unsigned num = 0;
     while (it.next() != TextBreakDone)
         ++num;
     return num;
 }
 
+unsigned numCharactersInGraphemeClusters(const String& string, unsigned numGraphemeClusters)

[eae, 2015/05/14 23:52:48]

We already have an implementation of this in HarfBuzzShaper,
countGraphemesInCluster. How about we move that implementation into
TextBreakIterator and make it a static function? That way the implementation can
be shared.

[changseok, 2015/05/15 17:08:56]

Sorry, I can't follow this meaning. Do you want anything like..
static unsigned countGraphemesInCluster()
{
    ....
}

unsigned numCharactersInGraphemeClutters()
{
    ....
    return countGraphemesInClusters();
}

??

+{
+    unsigned stringLength = string.length();
+
+    if (!stringLength)
+        return 0;
+
+    // The only Latin-1 Extended Grapheme Cluster is CR LF
+    if (string.is8Bit() && !string.contains('\r'))
+        return std::min(stringLength, numGraphemeClusters);
+
+    NonSharedCharacterBreakIterator it(string);
+    if (!it)
+        return std::min(stringLength, numGraphemeClusters);
+
+    for (unsigned i = 0; i < numGraphemeClusters; ++i) {
+        if (it.next() == TextBreakDone)
+            return stringLength;
+    }
+    return it.current();
+}
 
 static inline bool isBreakableSpace(UChar ch)
 {
     switch (ch) {
     case ' ':
     case '\n':
     case '\t':
         return true;
     default:
         return false;
@@ skipping 224 matching lines @@
 }
 
 int LazyLineBreakIterator::nextBreakablePositionKeepAll(int pos)
 {
     if (m_string.is8Bit())
         return nextBreakablePosition<LChar>(*this, m_string.characters8(), m_string.length(), pos);
     return nextBreakablePositionKeepAllInternal(*this, m_string.characters16(), m_string.length(), pos);
 }
 
 } // namespace blink