Replace StringImpl::empty{16Bit}() with a static member

third_party/WebKit/Source/wtf/text/StringImpl.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2009 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 187 matching lines @@
       : m_refCount(1),
         m_length(length),
         m_hash(hash),
         m_containsOnlyASCII(!length),
         m_needsASCIICheck(static_cast<bool>(length)),
         m_isAtomic(false),
         m_is8Bit(true),
         m_isStatic(true) {}
 
  public:
+  static StringImpl* empty;
+  static StringImpl* empty16Bit;
+
   ~StringImpl();
 
+  static void initStatics();
+
   static StringImpl* createStatic(const char* string,
                                   unsigned length,
                                   unsigned hash);
   static void reserveStaticStringsCapacityForSize(unsigned size);
   static void freezeStaticStrings();
   static const StaticStringsTable& allStaticStrings();
   static unsigned highestStaticStringLength() {
     return m_highestStaticStringLength;
   }
 
@@ skipping 97 matching lines @@
 
   ALWAYS_INLINE void deref() const {
 #if DCHECK_IS_ON()
     DCHECK(isStatic() || m_verifier.onDeref(m_refCount))
         << asciiForDebugging() << " " << currentThread();
 #endif
     if (!--m_refCount)
       destroyIfNotStatic();
   }
 
-  static StringImpl* empty();
-  static StringImpl* empty16Bit();
-
   // FIXME: Does this really belong in StringImpl?
   template <typename T>
   static void copyChars(T* destination,
                         const T* source,
                         unsigned numCharacters) {
     memcpy(destination, source, numCharacters * sizeof(T));
   }
 
   ALWAYS_INLINE static void copyChars(UChar* destination,
                                       const LChar* source,
@@ skipping 545 matching lines @@
 using WTF::TextCaseASCIIInsensitive;
 using WTF::TextCaseUnicodeInsensitive;
 using WTF::TextCaseSensitive;
 using WTF::TextCaseSensitivity;
 using WTF::equal;
 using WTF::equalNonNull;
 using WTF::lengthOfNullTerminatedString;
 using WTF::reverseFind;
 
 #endif