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

components/offline_pages/stub_offline_page_model.h

 // 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.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_STUB_OFFLINE_PAGE_MODEL_H_
 #define COMPONENTS_OFFLINE_PAGES_STUB_OFFLINE_PAGE_MODEL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 18 matching lines @@
                 int64_t proposed_offline_id,
                 std::unique_ptr<OfflinePageArchiver> archiver,
                 const SavePageCallback& callback) override;
   void MarkPageAccessed(int64_t offline_id) override;
   void ClearAll(const base::Closure& callback) override;
   void DeletePagesByOfflineId(const std::vector<int64_t>& offline_ids,
                               const DeletePageCallback& callback) override;
   void DeleteCachedPagesByURLPredicate(
       const UrlPredicate& predicate,
       const DeletePageCallback& callback) override;
-  void HasPages(const std::string& name_space,
-                const HasPagesCallback& callback) override;
   void CheckPagesExistOffline(
       const std::set<GURL>& urls,
       const CheckPagesExistOfflineCallback& callback) override;
   void GetAllPages(const MultipleOfflinePageItemCallback& callback) override;
   void GetAllPagesWithExpired(
       const MultipleOfflinePageItemCallback& callback) override;
   void GetOfflineIdsForClientId(
       const ClientId& client_id,
       const MultipleOfflineIdCallback& callback) override;
   const std::vector<int64_t> MaybeGetOfflineIdsForClientId(
@@ skipping 21 matching lines @@
   bool is_loaded() const override;
   OfflineEventLogger* GetLogger() override;
 
  private:
   std::vector<int64_t> offline_ids_;
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_STUB_OFFLINE_PAGE_MODEL_H_