DOMTokenList: Update serialization algorithm on add()/remove()

third_party/WebKit/Source/core/dom/SpaceSplitString.cpp

 /*
  * Copyright (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2007, 2008, 2011, 2012 Apple 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 98 matching lines @@
   vector_.erase(index);
 }
 
 void SpaceSplitString::Add(const AtomicString& string) {
   // FIXME: add() does not allow duplicates but createVector() does.
   if (Contains(string))
     return;
   EnsureUnique();
   if (data_)
     data_->Add(string);
+  else
+    data_ = Data::Create(string);
 }
 
 bool SpaceSplitString::Remove(const AtomicString& string) {
   if (!data_)
     return false;
   unsigned i = 0;
   bool changed = false;
   while (i < data_->size()) {
     if ((*data_)[i] == string) {
       if (!changed)
@@ skipping 54 matching lines @@
   CreateVector(string);
 }
 
 SpaceSplitString::Data::Data(const SpaceSplitString::Data& other)
     : RefCounted<Data>(), vector_(other.vector_) {
   // Note that we don't copy m_keyString to indicate to the destructor that
   // there's nothing to be removed from the sharedDataMap().
 }
 
 }  // namespace blink