Add noBarrierStore to WTF and use it for spinlocks

third_party/WebKit/Source/wtf/Atomics.h

 /*
  * Copyright (C) 2007, 2008, 2010, 2012 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 301 matching lines @@
 {
     *ptr = value;
 }
 
 ALWAYS_INLINE float noBarrierLoad(volatile const float* ptr)
 {
     float value = *ptr;
     return value;
 }
 
+ALWAYS_INLINE void noBarrierStore(volatile int* ptr, int value)
+{
+    *ptr = value;
+}
+
+ALWAYS_INLINE int noBarrierLoad(volatile const int* ptr)
+{
+    int value = *ptr;
+    return value;
+}
+
 #if defined(ADDRESS_SANITIZER)
 
 NO_SANITIZE_ADDRESS ALWAYS_INLINE void asanUnsafeReleaseStore(volatile unsigned* ptr, unsigned value)
 {
     MEMORY_BARRIER();
     *ptr = value;
 }
 
 NO_SANITIZE_ADDRESS ALWAYS_INLINE unsigned asanUnsafeAcquireLoad(volatile const unsigned* ptr)
 {
@@ skipping 35 matching lines @@
 using WTF::noBarrierLoad;
 using WTF::noBarrierStore;
 
 // These methods allow loading from and storing to poisoned memory. Only
 // use these methods if you know what you are doing since they will
 // silence use-after-poison errors from ASan.
 using WTF::asanUnsafeAcquireLoad;
 using WTF::asanUnsafeReleaseStore;
 
 #endif // Atomics_h