Load offline page if reading list entry takes more than 1s to load.

ios/web/public/navigation_item.h

 // Copyright 2014 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 IOS_WEB_PUBLIC_NAVIGATION_ITEM_H_
 #define IOS_WEB_PUBLIC_NAVIGATION_ITEM_H_
 
 #include <memory>
 
 #include "base/strings/string16.h"
@@ skipping 99 matching lines @@
 
   // |true| if this item is the result of a POST request with data.
   virtual bool HasPostData() const = 0;
 
   // Returns the item's current http request headers.
   virtual NSDictionary* GetHttpRequestHeaders() const = 0;
 
   // Adds headers from |additional_headers| to the item's http request headers.
   // Existing headers with the same key will be overridden.
   virtual void AddHttpRequestHeaders(NSDictionary* additional_headers) = 0;
+
+  virtual NSDictionary* GetExtraData() const = 0;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_NAVIGATION_ITEM_H_