Revert of Remove ref_counted.cc

base/memory/ref_counted.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/ref_counted.h"
+#include "base/threading/thread_collision_warner.h"
+
+namespace base {
+
+namespace subtle {
+
+bool RefCountedThreadSafeBase::HasOneRef() const {
+  return AtomicRefCountIsOne(
+      &const_cast<RefCountedThreadSafeBase*>(this)->ref_count_);
+}
+
+RefCountedThreadSafeBase::RefCountedThreadSafeBase() : ref_count_(0) {
+#ifndef NDEBUG
+  in_dtor_ = false;
+#endif
+}
+
+RefCountedThreadSafeBase::~RefCountedThreadSafeBase() {
+#ifndef NDEBUG
+  DCHECK(in_dtor_) << "RefCountedThreadSafe object deleted without "
+                      "calling Release()";
+#endif
+}
+
+void RefCountedThreadSafeBase::AddRef() const {
+#ifndef NDEBUG
+  DCHECK(!in_dtor_);
+#endif
+  AtomicRefCountInc(&ref_count_);
+}
+
+bool RefCountedThreadSafeBase::Release() const {
+#ifndef NDEBUG
+  DCHECK(!in_dtor_);
+  DCHECK(!AtomicRefCountIsZero(&ref_count_));
+#endif
+  if (!AtomicRefCountDec(&ref_count_)) {
+#ifndef NDEBUG
+    in_dtor_ = true;
+#endif
+    return true;
+  }
+  return false;
+}
+
+}  // namespace subtle
+
+}  // namespace base