Reorganize net/disk_cache into backend specific directories.

net/disk_cache/file_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 "net/disk_cache/file_lock.h"
-
-#include "base/atomicops.h"
-
-namespace {
-
-void Barrier() {
-#if !defined(COMPILER_MSVC)
-  // VS uses memory barrier semantics for volatiles.
-  base::subtle::MemoryBarrier();
-#endif
-}
-
-}  // namespace
-
-namespace disk_cache {
-
-FileLock::FileLock(BlockFileHeader* header) {
-  updating_ = &header->updating;
-  (*updating_)++;
-  Barrier();
-  acquired_ = true;
-}
-
-FileLock::~FileLock() {
-  Unlock();
-}
-
-void FileLock::Lock() {
-  if (acquired_)
-    return;
-  (*updating_)++;
-  Barrier();
-}
-
-void FileLock::Unlock() {
-  if (!acquired_)
-    return;
-  Barrier();
-  (*updating_)--;
-}
-
-}  // namespace disk_cache