[NTP::RecentTabs] Do not fetch all pages when not a recent tab is added.

components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.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/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 51 matching lines @@
 };
 
 std::unique_ptr<OfflinePageModelQuery> BuildRecentTabsQuery(
     offline_pages::OfflinePageModel* model) {
   OfflinePageModelQueryBuilder builder;
   builder.RequireShownAsRecentlyVisitedSite(
       OfflinePageModelQuery::Requirement::INCLUDE_MATCHING);
   return builder.Build(model->GetPolicyController());
 }
 
+bool IsClientIdForOfflinePageRecentTab(

[jkrcal, 2016/12/21 12:08:29]

nit: hard to parse (with the standard coding convention to omit articles ;)

What about just IsRecentTab?
 (maybe with renaming the second arg to offline_page_client_id)

[vitaliii, 2016/12/21 13:39:07]

Done.

IsRecentTab with OfflinePageItem as the second argument.

+    offline_pages::ClientPolicyController* policy_controller,
+    const offline_pages::ClientId& client_id) {
+  return policy_controller->IsShownAsRecentlyVisitedSite(client_id.name_space);
+}
+
 }  // namespace
 
 RecentTabSuggestionsProvider::RecentTabSuggestionsProvider(
     ContentSuggestionsProvider::Observer* observer,
     offline_pages::OfflinePageModel* offline_page_model,
     PrefService* pref_service)
     : ContentSuggestionsProvider(observer),
       category_status_(CategoryStatus::AVAILABLE_LOADING),
       provided_category_(
           Category::FromKnownCategory(KnownCategories::RECENT_TABS)),
@@ skipping 123 matching lines @@
   callback.Run(std::move(suggestions));
 }
 
 void RecentTabSuggestionsProvider::OfflinePageModelLoaded(
     offline_pages::OfflinePageModel* model) {}
 
 void RecentTabSuggestionsProvider::OfflinePageAdded(
     offline_pages::OfflinePageModel* model,
     const offline_pages::OfflinePageItem& added_page) {
   DCHECK_EQ(offline_page_model_, model);
-  FetchRecentTabs();
+  if (IsClientIdForOfflinePageRecentTab(model->GetPolicyController(),

[jkrcal, 2016/12/21 12:08:29]

nit: 

If easy to set up, can you add a unit-test to check that it is not fetched when
it is a non-Recent-Tab offline page is added?

If not easy to do, just skip it. This is not an important functionality.

[vitaliii, 2016/12/21 13:39:07]

Done.

+                                        added_page.client_id)) {
+    FetchRecentTabs();
+  }
 }
 
 void RecentTabSuggestionsProvider::
     GetPagesMatchingQueryCallbackForFetchRecentTabs(
         const std::vector<OfflinePageItem>& offline_pages) {
   NotifyStatusChanged(CategoryStatus::AVAILABLE);
   std::set<std::string> old_dismissed_ids = ReadDismissedIDsFromPrefs();
   std::set<std::string> new_dismissed_ids;
   std::vector<const OfflinePageItem*> recent_tab_items;
   for (const OfflinePageItem& item : offline_pages) {
@@ skipping 111 matching lines @@
 }
 
 void RecentTabSuggestionsProvider::StoreDismissedIDsToPrefs(
     const std::set<std::string>& dismissed_ids) {
   prefs::StoreDismissedIDsToPrefs(pref_service_,
                                   prefs::kDismissedRecentOfflineTabSuggestions,
                                   dismissed_ids);
 }
 
 }  // namespace ntp_snippets