[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)

[carlosk, 2017/05/03 18:13:52]

nit: use < instead of <= to avoid overlapping ranges.

[romax, 2017/05/03 19:46:21]

Done.

+      total_size += page.file_size;
+  }
+  callback.Run(total_size);
+}
+
+}  // namespace
+
+namespace offline_pages {
+
+// static
+void CachedOfflinePageUtils::GetCachedOfflinePageSizeBetween(
+    OfflinePageModel* model,
+    const SizeCalculatedCallback& callback,
+    const base::Time& begin_time,
+    const base::Time& end_time) {
+  if (!model)
+    callback.Run(0);

[carlosk, 2017/05/03 18:13:52]

Change this to a DCHECK instead. It should be the responsibility of the caller
to deal with the case of an nonexistent model instead of receiving a zero value
for the cache size and be ignorant the error.

[romax, 2017/05/03 19:46:21]

Done.

+  OfflinePageModelQueryBuilder builder;
+  builder.RequireRemovedOnCacheReset(
+      OfflinePageModelQuery::Requirement::INCLUDE_MATCHING);
+  model->GetPagesMatchingQuery(
+      builder.Build(model->GetPolicyController()),
+      base::Bind(&DoCalculateSizeBetween, callback, begin_time, end_time));
+}
+
+// static
+void CachedOfflinePageUtils::GetCachedOfflinePageSize(
+    OfflinePageModel* model,
+    const SizeCalculatedCallback& callback) {
+  GetCachedOfflinePageSizeBetween(model, callback, base::Time(),
+                                  base::Time::Now());

[carlosk, 2017/05/03 18:13:52]

Switch to base::Time::Max() for unbounded upper limits as done in other cache
calculating code.

[romax, 2017/05/03 19:46:21]

Done.

+}
+
+// static
+void CachedOfflinePageUtils::DeleteCachedOfflinePage(
+    OfflinePageModel* model,
+    const DeletePageCallback& callback) {
+  if (!model)
+    callback.Run(DeletePageResult::STORE_FAILURE);

[carlosk, 2017/05/03 18:13:52]

nit: should probably change this to a DCHECK too? I'm unsure because so far
there's no caller apart from test code.

[romax, 2017/05/03 19:46:21]

Removed the unused methods.

+  OfflinePageModelQueryBuilder builder;
+  builder.RequireRemovedOnCacheReset(
+      OfflinePageModelQuery::Requirement::INCLUDE_MATCHING);
+  model->DeletePagesMatchingQuery(builder.Build(model->GetPolicyController()),
+                                  callback);
+}
+}  // namespace offline_pages