[cros] RlzValueStore made protected by a cross-process lock and not persisted over browser lifetime…

rlz/lib/recursive_lock.cc

-// Copyright (c) 2012 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 "rlz/lib/recursive_lock.h"
-
-#include "base/logging.h"
-
-namespace rlz_lib {
-
-RecursiveLock::RecursiveLock()
-    : owner_(),
-      recursion_() {
-}
-
-RecursiveLock::~RecursiveLock() {
-}
-
-void RecursiveLock::Acquire() {
-  base::subtle::Atomic32 me = base::PlatformThread::CurrentId();
-  if (me != base::subtle::NoBarrier_Load(&owner_)) {
-    lock_.Acquire();
-    DCHECK(!recursion_);
-    DCHECK(!owner_);
-    base::subtle::NoBarrier_Store(&owner_, me);
-  }
-  ++recursion_;
-}
-
-void RecursiveLock::Release() {
-  DCHECK_EQ(base::subtle::NoBarrier_Load(&owner_),
-            base::PlatformThread::CurrentId());
-  DCHECK_GT(recursion_, 0);
-  if (!--recursion_) {
-    base::subtle::NoBarrier_Store(&owner_, 0);
-    lock_.Release();
-  }
-}
-
-}  // namespace rlz_lib