Tidy DEFINE_(THREAD_SAFE_)STATIC_LOCAL() implementations.

third_party/WebKit/Source/wtf/Threading.h

 /*
  * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
  *
  * 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
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 17 matching lines @@
  */
 
 #ifndef Threading_h
 #define Threading_h
 
 #include "wtf/Atomics.h"
 #include "wtf/TypeTraits.h"
 #include "wtf/WTFExport.h"
 #include <stdint.h>
 
-// For portability, we do not make use of C++11 thread-safe statics, as
-// supported by some toolchains. Make use of double-checked locking to reduce
-// overhead.  Note that this uses system-wide default lock, and cannot be used
-// before WTF::initializeThreading() is called.
-#define DEFINE_THREAD_SAFE_STATIC_LOCAL(T, name, initializer)             \
-  static_assert(!WTF::IsGarbageCollectedType<T>::value,                   \
-                "Garbage collected types should not be a static local!"); \
-  /* Init to nullptr is thread-safe on all implementations. */            \
-  static void* name##Pointer = nullptr;                                   \
-  if (!WTF::acquireLoad(&name##Pointer)) {                                \
-    WTF::lockAtomicallyInitializedStaticMutex();                          \
-    if (!WTF::acquireLoad(&name##Pointer)) {                              \
-      std::remove_const<T>::type* initializerResult = initializer;        \
-      WTF::releaseStore(&name##Pointer, initializerResult);               \
-    }                                                                     \
-    WTF::unlockAtomicallyInitializedStaticMutex();                        \
-  }                                                                       \
-  T& name = *static_cast<T*>(name##Pointer)
-
 namespace WTF {
 
 #if OS(WIN)
 typedef uint32_t ThreadIdentifier;
 #else
 typedef intptr_t ThreadIdentifier;
 #endif
 
 namespace internal {
 WTF_EXPORT ThreadIdentifier currentThreadSyscall();
 }  // namespace internal
 
 WTF_EXPORT ThreadIdentifier currentThread();
 
-WTF_EXPORT void lockAtomicallyInitializedStaticMutex();
-WTF_EXPORT void unlockAtomicallyInitializedStaticMutex();
-
 #if DCHECK_IS_ON()
-WTF_EXPORT bool isAtomicallyInitializedStaticMutexLockHeld();
 WTF_EXPORT bool isBeforeThreadCreated();
 WTF_EXPORT void willCreateThread();
 #endif
 
 }  // namespace WTF
 
 using WTF::ThreadIdentifier;
 using WTF::currentThread;
 
 #endif  // Threading_h