Move CrossThreadCopier from platform/ to wtf/

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 957 matching lines @@
                 out.setf(std::ios_base::hex, std::ios_base::basefield);
                 out.setf(std::ios::uppercase);
                 out << character;
             }
             break;
         }
     }
     return out << '"';
 }
 
+CrossThreadCopier<String>::Type CrossThreadCopier<String>::copy(const String& str)
+{
+    return str.isolatedCopy();
+}
+
 } // namespace WTF
 
 #ifndef NDEBUG
 // For use in the debugger
 String* string(const char*);
 Vector<char> asciiDebug(StringImpl*);
 Vector<char> asciiDebug(String&);
 
 void String::show() const
 {
@@ skipping 27 matching lines @@
     buffer.append('\0');
     return buffer;
 }
 
 Vector<char> asciiDebug(String& string)
 {
     return asciiDebug(string.impl());
 }
 
 #endif