Makes the OfflinePageBridge.getAllPages method asynchronous.

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 471938e19ccb192f41e339f917c0bce1ff18496e..e904659456baa7e2ff18f82031bc4224e61fe820 100644
--- a/components/offline_pages/offline_page_model.h
+++ b/components/offline_pages/offline_page_model.h
@@ -165,11 +165,6 @@ class OfflinePageModel : public KeyedService,
   void MarkPageForDeletion(int64_t bookmark_id,
                            const DeletePageCallback& callback);
 
-  // Deletes an offline page related to the passed |bookmark_id|. Requires that
-  // the model is loaded.
-  void DeletePageByBookmarkId(int64_t bookmark_id,
-                              const DeletePageCallback& callback);
-
   // Deletes offline pages related to the passed |bookmark_ids|. Requires that
   // the model is loaded.
   void DeletePagesByBookmarkId(const std::vector<int64_t>& bookmark_ids,