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

components/offline_pages/offline_page_model.h

Index: components/offline_pages/offline_page_model.h
diff --git a/components/offline_pages/offline_page_model.h b/components/offline_pages/offline_page_model.h
index 59034dac60fbd09b760a2d319aee0f7ce6ac8981..7a4423f88b3bfe91a6fdd9376ae8b8e039bc17c7 100644
--- a/components/offline_pages/offline_page_model.h
+++ b/components/offline_pages/offline_page_model.h
@@ -108,11 +108,6 @@ class OfflinePageModel : public base::SupportsUserData {
       const UrlPredicate& predicate,
       const DeletePageCallback& callback) = 0;
 
-  // Returns true via callback if there are offline pages in the given
-  // |name_space|.
-  virtual void HasPages(const std::string& name_space,
-                        const HasPagesCallback& callback) = 0;
-
   // Returns via callback all GURLs in |urls| that are equal to the online URL
   // of any offline page.
   virtual void CheckPagesExistOffline(