Make browsing_data component a layered component

components/browsing_data/conditional_cache_deletion_helper.cc

-// Copyright 2016 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 "components/browsing_data/conditional_cache_deletion_helper.h"
-
-#include "base/callback.h"
-#include "base/location.h"
-#include "base/single_thread_task_runner.h"
-#include "base/threading/thread_task_runner_handle.h"
-#include "content/public/browser/browser_thread.h"
-
-namespace {
-
-bool EntryPredicateFromURLsAndTime(
-    const base::Callback<bool(const GURL&)>& url_predicate,
-    const base::Time& begin_time,
-    const base::Time& end_time,
-    const disk_cache::Entry* entry) {
-  return (entry->GetLastModified() >= begin_time &&
-          entry->GetLastModified() < end_time &&
-          url_predicate.Run(GURL(entry->GetKey())));
-}
-
-}  // namespace
-
-namespace browsing_data {
-
-ConditionalCacheDeletionHelper::ConditionalCacheDeletionHelper(
-    disk_cache::Backend* cache,
-    const base::Callback<bool(const disk_cache::Entry*)>& condition)
-        : cache_(cache),
-          condition_(condition),
-          current_entry_(nullptr),
-          previous_entry_(nullptr) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-}
-
-// static
-base::Callback<bool(const disk_cache::Entry*)>
-ConditionalCacheDeletionHelper::CreateURLAndTimeCondition(
-    const base::Callback<bool(const GURL&)>& url_predicate,
-    const base::Time& begin_time,
-    const base::Time& end_time) {
-  return base::Bind(
-      &EntryPredicateFromURLsAndTime,
-      url_predicate,
-      begin_time.is_null() ? base::Time() : begin_time,
-      end_time.is_null() ? base::Time::Max() : end_time);
-}
-
-int ConditionalCacheDeletionHelper::DeleteAndDestroySelfWhenFinished(
-    const net::CompletionCallback& completion_callback) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
-
-  completion_callback_ = completion_callback;
-  iterator_ = cache_->CreateIterator();
-
-  IterateOverEntries(net::OK);
-  return net::ERR_IO_PENDING;
-}
-
-ConditionalCacheDeletionHelper::~ConditionalCacheDeletionHelper() {
-}
-
-void ConditionalCacheDeletionHelper::IterateOverEntries(int error) {
-  while (error != net::ERR_IO_PENDING) {
-    // If the entry obtained in the previous iteration matches the condition,
-    // mark it for deletion. The iterator is already one step forward, so it
-    // won't be invalidated. Always close the previous entry so it does not
-    // leak.
-    if (previous_entry_) {
-      if (condition_.Run(previous_entry_))
-        previous_entry_->Doom();
-      previous_entry_->Close();
-    }
-
-    if (error == net::ERR_FAILED) {
-      // The iteration finished successfuly or we can no longer iterate
-      // (e.g. the cache was destroyed). We cannot distinguish between the two,
-      // but we know that there is nothing more that we can do, so we return OK.
-      base::MessageLoop::current()->task_runner()->PostTask(
-          FROM_HERE, base::Bind(completion_callback_, net::OK));
-      base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, this);
-      return;
-    }
-
-    previous_entry_ = current_entry_;
-    error = iterator_->OpenNextEntry(
-        &current_entry_,
-        base::Bind(&ConditionalCacheDeletionHelper::IterateOverEntries,
-                   base::Unretained(this)));
-  }
-}
-
-}  // namespace browsing_data