Add "Show saved copy" button in dino page when there's offline copy

chrome/browser/net/net_error_tab_helper.h

Index: chrome/browser/net/net_error_tab_helper.h
diff --git a/chrome/browser/net/net_error_tab_helper.h b/chrome/browser/net/net_error_tab_helper.h
index ef4b6198ccad94451fe9feb4e8357089a196eab5..f1ffac9be25c32c20837ba5d339ed1d70d29316d 100644
--- a/chrome/browser/net/net_error_tab_helper.h
+++ b/chrome/browser/net/net_error_tab_helper.h
@@ -104,8 +104,9 @@ class NetErrorTabHelper
 
   // Relates to offline pages handling.
 #if defined(OS_ANDROID)
-  void SetHasOfflinePages(content::RenderFrameHost* render_frame_host);
+  void SetOfflinePageInfo(content::RenderFrameHost* render_frame_host);
   void ShowOfflinePages();
+  void LoadOfflineCopy(const GURL& url);
 #endif
 
   // True if the last provisional load that started was for an error page.