[Offline Pages] Removes the unused "HasPages" function.

components/offline_pages/stub_offline_page_model.cc

Index: components/offline_pages/stub_offline_page_model.cc
diff --git a/components/offline_pages/stub_offline_page_model.cc b/components/offline_pages/stub_offline_page_model.cc
index 5afc3d5baa544b521f0e1bb18158011f1cb341c4..d9c394bf851b1a4ccc2cd543f2ea44aa88bd59e2 100644
--- a/components/offline_pages/stub_offline_page_model.cc
+++ b/components/offline_pages/stub_offline_page_model.cc
@@ -25,8 +25,6 @@ void StubOfflinePageModel::DeletePagesByOfflineId(
 void StubOfflinePageModel::DeleteCachedPagesByURLPredicate(
     const UrlPredicate& predicate,
     const DeletePageCallback& callback) {}
-void StubOfflinePageModel::HasPages(const std::string& name_space,
-                                    const HasPagesCallback& callback) {}
 void StubOfflinePageModel::CheckPagesExistOffline(
     const std::set<GURL>& urls,
     const CheckPagesExistOfflineCallback& callback) {}