Move Source/WTF/wtf to Source/wtf

Source/wtf/dtoa/double-conversion.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 586 matching lines @@
         buffer[buffer_pos] = '\0';
         
         double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent);
         *processed_characters_count = current - input;
         return sign? -converted: converted;
     }
     
 }  // namespace double_conversion
 
 } // namespace WTF