Add noBarrierStore to WTF and use it for spinlocks

third_party/WebKit/Source/wtf/SpinLock.cpp

Index: third_party/WebKit/Source/wtf/SpinLock.cpp
diff --git a/third_party/WebKit/Source/wtf/SpinLock.cpp b/third_party/WebKit/Source/wtf/SpinLock.cpp
index 0b5586e66cb899ad71f3763bfe623f5754ab2112..f958c0fbf956154d00feb0031532a73568fc3f29 100644
--- a/third_party/WebKit/Source/wtf/SpinLock.cpp
+++ b/third_party/WebKit/Source/wtf/SpinLock.cpp
@@ -62,13 +62,13 @@ void slowSpinLockLock(int volatile* lock)
             for (int count = 0; count < kYieldProcessorTries; ++count) {
                 // Let the Processor know we're spinning.
                 YIELD_PROCESSOR;
-                if (!*lock && LIKELY(!atomicTestAndSetToOne(lock)))
+                if (!noBarrierLoad(lock) && LIKELY(!atomicTestAndSetToOne(lock)))
                     return;
             }
 
             // Give the OS a chance to schedule something on this core.
             YIELD_THREAD;
-        } while (*lock);
+        } while (noBarrierLoad(lock));
     } while (UNLIKELY(atomicTestAndSetToOne(lock)));
 }