Move String::isSafeToSendToAnotherThread to StringImpl.

third_party/WebKit/Source/wtf/text/WTFString.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007-2009 Torch Mobile, Inc.
  *
  * 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 553 matching lines @@
 
 String String::isolatedCopy() const
 {
     if (!m_impl)
         return String();
     return m_impl->isolatedCopy();
 }
 
 bool String::isSafeToSendToAnotherThread() const
 {
-    if (!impl())
-        return true;
-    if (impl()->isStatic())
-        return true;
-    // AtomicStrings are not safe to send between threads as ~StringImpl()
-    // will try to remove them from the wrong AtomicStringTable.
-    if (impl()->isAtomic())
-        return false;
-    if (impl()->hasOneRef())
-        return true;
-    return false;
+    return !m_impl || m_impl->isSafeToSendToAnotherThread();
 }
 
 void String::split(const String& separator, bool allowEmptyEntries, Vector<String>& result) const
 {
     result.clear();
 
     unsigned startPos = 0;
     size_t endPos;
     while ((endPos = find(separator, startPos)) != kNotFound) {
         if (allowEmptyEntries || startPos != endPos)
@@ skipping 341 matching lines @@
     buffer.append('\0');
     return buffer;
 }
 
 Vector<char> asciiDebug(String& string)
 {
     return asciiDebug(string.impl());
 }
 
 #endif