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

chrome/browser/android/offline_pages/offline_page_utils.cc

Index: chrome/browser/android/offline_pages/offline_page_utils.cc
diff --git a/chrome/browser/android/offline_pages/offline_page_utils.cc b/chrome/browser/android/offline_pages/offline_page_utils.cc
index 48dda928449c6dea04058e40600f8323dc871da5..97e5dbc3f374d472e29e76dde776d9ce87348214 100644
--- a/chrome/browser/android/offline_pages/offline_page_utils.cc
+++ b/chrome/browser/android/offline_pages/offline_page_utils.cc
@@ -129,6 +129,19 @@ void CheckDuplicateOngoingDownloads(
       request_coordinator_continuation, browser_context, url, callback));
 }
 
+void DoCalculateSizeBetween(
+    const offline_pages::SizeInBytesCallback& 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;

[carlosk, 2017/05/05 18:20:27]

The interval here should be  closed-open, where the start time is included and
the end time is excluded. This is so that sequential intervals are both a)
continuous and b) don't overlap. So the begin time comparison should use <=
(closed limit) and the end time should use < (open limit). 

This might sound like nit picking but in the not so uncommon case of using
"exact" times (like April 4th 2016, 00:00:00) for both entries and search
ranges, then not being careful about this matter could cause entries to either
not show up or appear twice in sequential ranges.

[romax, 2017/05/05 21:01:30]

Done.

+  }
+  callback.Run(total_size);
+}
+
 }  // namespace
 
 // static
@@ -308,4 +321,23 @@ bool OfflinePageUtils::CanDownloadAsOfflinePage(
           net::MatchesMimeType(contents_mime_type, "application/xhtml+xml"));
 }
 
+// static
+bool OfflinePageUtils::GetCachedOfflinePageSizeBetween(
+    content::BrowserContext* browser_context,
+    const SizeInBytesCallback& callback,
+    const base::Time& begin_time,
+    const base::Time& end_time) {
+  OfflinePageModel* offline_page_model =
+      OfflinePageModelFactory::GetForBrowserContext(browser_context);
+  if (!offline_page_model || begin_time > end_time)
+    return false;
+  OfflinePageModelQueryBuilder builder;
+  builder.RequireRemovedOnCacheReset(
+      OfflinePageModelQuery::Requirement::INCLUDE_MATCHING);
+  offline_page_model->GetPagesMatchingQuery(
+      builder.Build(offline_page_model->GetPolicyController()),
+      base::Bind(&DoCalculateSizeBetween, callback, begin_time, end_time));
+  return true;
+}
+
 }  // namespace offline_pages