Move base to DEPS

base/memory/singleton.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/memory/singleton.h"
-#include "base/threading/platform_thread.h"
-
-namespace base {
-namespace internal {
-
-subtle::AtomicWord WaitForInstance(subtle::AtomicWord* instance) {
-  // Handle the race. Another thread beat us and either:
-  // - Has the object in BeingCreated state
-  // - Already has the object created...
-  // We know value != NULL.  It could be kBeingCreatedMarker, or a valid ptr.
-  // Unless your constructor can be very time consuming, it is very unlikely
-  // to hit this race.  When it does, we just spin and yield the thread until
-  // the object has been created.
-  subtle::AtomicWord value;
-  while (true) {
-    // The load has acquire memory ordering as the thread which reads the
-    // instance pointer must acquire visibility over the associated data.
-    // The pairing Release_Store operation is in Singleton::get().
-    value = subtle::Acquire_Load(instance);
-    if (value != kBeingCreatedMarker)
-      break;
-    PlatformThread::YieldCurrentThread();
-  }
-  return value;
-}
-
-}  // namespace internal
-}  // namespace base
-