CPU profiler: make code events handling scalable.

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index bee517364a2fc879dbc3f661a33546140323219d..e2d123cd1ba53ff385eb6de70d488bec1a5528d9 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -1340,6 +1340,12 @@ int OS::ActivationFrameAlignment() {
 }
 
 
+void OS::ReleaseStore(volatile AtomicWord* ptr, AtomicWord value) {
+  MemoryBarrier();
+  *ptr = value;
+}
+
+
 bool VirtualMemory::IsReserved() {
   return address_ != NULL;
 }