Cleanup: given that TLS slot can't fail to initialize, remove bool return values

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 54928ede272526bc4ac24bc4621facecfc9b9eee..0bb396cfd7966fbe493b43683f4bb59a5561c9ce 100644
--- a/base/threading/thread_local_storage.cc
+++ b/base/threading/thread_local_storage.cc
@@ -197,7 +197,7 @@ ThreadLocalStorage::Slot::Slot(TLSDestructorFunc destructor) {
   Initialize(destructor);
 }
 
-bool ThreadLocalStorage::StaticSlot::Initialize(TLSDestructorFunc destructor) {
+void ThreadLocalStorage::StaticSlot::Initialize(TLSDestructorFunc destructor) {
   PlatformThreadLocalStorage::TLSKey key =
       base::subtle::NoBarrier_Load(&g_native_tls_key);
   if (key == PlatformThreadLocalStorage::TLS_KEY_OUT_OF_INDEXES ||
@@ -212,7 +212,6 @@ bool ThreadLocalStorage::StaticSlot::Initialize(TLSDestructorFunc destructor) {
   // Setup our destructor.
   g_tls_destructors[slot_] = destructor;
   initialized_ = true;
-  return true;
 }
 
 void ThreadLocalStorage::StaticSlot::Free() {