Fix a race in ThreadLocalStorage::StaticSlot::initialized which triggers a TSAN error.

base/threading/thread_local_storage.cc

Index: base/threading/thread_local_storage.cc
diff --git a/base/threading/thread_local_storage.cc b/base/threading/thread_local_storage.cc
index 0bb396cfd7966fbe493b43683f4bb59a5561c9ce..701f6a2af9bf5afd1ae12c4b89fc387963ced92d 100644
--- a/base/threading/thread_local_storage.cc
+++ b/base/threading/thread_local_storage.cc
@@ -192,8 +192,8 @@ void PlatformThreadLocalStorage::OnThreadExit(void* value) {
 }  // namespace internal
 
 ThreadLocalStorage::Slot::Slot(TLSDestructorFunc destructor) {
-  initialized_ = false;
   slot_ = 0;
+  base::subtle::Release_Store(&initialized_, 0);
   Initialize(destructor);
 }
 
@@ -211,7 +211,7 @@ void ThreadLocalStorage::StaticSlot::Initialize(TLSDestructorFunc destructor) {
 
   // Setup our destructor.
   g_tls_destructors[slot_] = destructor;
-  initialized_ = true;
+  base::subtle::Release_Store(&initialized_, 1);
 }
 
 void ThreadLocalStorage::StaticSlot::Free() {
@@ -221,7 +221,7 @@ void ThreadLocalStorage::StaticSlot::Free() {
   DCHECK_LT(slot_, kThreadLocalStorageSize);
   g_tls_destructors[slot_] = NULL;
   slot_ = 0;
-  initialized_ = false;
+  base::subtle::Release_Store(&initialized_, 0);
 }
 
 void* ThreadLocalStorage::StaticSlot::Get() const {