[Offline Pages] Add cached offline page utils and show usage in settings.

components/offline_pages/core/cached_offline_page_utils.cc

+// Copyright 2017 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/offline_pages/core/cached_offline_page_utils.h"
+
+#include <stdint.h>
+
+#include "base/bind.h"
+#include "base/time/time.h"
+#include "components/offline_pages/core/offline_page_item.h"
+#include "components/offline_pages/core/offline_page_model.h"
+#include "components/offline_pages/core/offline_page_types.h"
+
+namespace {
+
+void DoCalculateSizeBetween(
+    const offline_pages::SizeCalculatedCallback& callback,
+    const base::Time& begin_time,
+    const base::Time& end_time,
+    const offline_pages::MultipleOfflinePageItemResult& result) {
+  int64_t total_size = 0;
+  for (auto& page : result) {
+    if (begin_time < page.creation_time && page.creation_time < end_time)
+      total_size += page.file_size;
+  }
+  callback.Run(total_size);
+}
+
+}  // namespace
+
+namespace offline_pages {
+
+void GetCachedOfflinePageSizeBetween(OfflinePageModel* model,
+                                     const SizeCalculatedCallback& callback,
+                                     const base::Time& begin_time,
+                                     const base::Time& end_time) {
+  DCHECK(model);
+  OfflinePageModelQueryBuilder builder;
+  builder.RequireRemovedOnCacheReset(
+      OfflinePageModelQuery::Requirement::INCLUDE_MATCHING);
+  model->GetPagesMatchingQuery(
+      builder.Build(model->GetPolicyController()),
+      base::Bind(&DoCalculateSizeBetween, callback, begin_time, end_time));
+}
+
+}  // namespace offline_pages