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

third_party/WebKit/Source/wtf/ThreadingPthreads.cpp

 /*
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
  * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 63 matching lines @@
 }
 
 }  // namespace internal
 
 static Mutex* atomicallyInitializedStaticMutex;
 
 void initializeThreading() {
   // This should only be called once.
   DCHECK(!atomicallyInitializedStaticMutex);
 
-  // StringImpl::empty() does not construct its static string in a threadsafe
-  // fashion, so ensure it has been initialized from here.
-  StringImpl::empty();
-  StringImpl::empty16Bit();
   atomicallyInitializedStaticMutex = new Mutex;
   wtfThreadData();
   initializeDates();
   // Force initialization of static DoubleToStringConverter converter variable
   // inside EcmaScriptConverter function while we are in single thread mode.
   double_conversion::DoubleToStringConverter::EcmaScriptConverter();
 }
 
 void lockAtomicallyInitializedStaticMutex() {
   DCHECK(atomicallyInitializedStaticMutex);
@@ skipping 148 matching lines @@
 }
 
 void willCreateThread() {
   s_threadCreated = true;
 }
 #endif
 
 }  // namespace WTF
 
 #endif  // OS(POSIX)