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

components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc

Index: components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
diff --git a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
index 6d689dbc17a334ba51b390aaf851538276813dc2..70f2dc75739b61bf326071df0f09b6ad6e24d42f 100644
--- a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
+++ b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
@@ -69,6 +69,12 @@ std::unique_ptr<OfflinePageModelQuery> BuildRecentTabsQuery(
   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(
@@ -212,7 +218,10 @@ 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::