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

chrome/renderer/net/net_error_page_controller.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 CHROME_RENDERER_NET_NET_ERROR_PAGE_CONTROLLER_H_
 #define CHROME_RENDERER_NET_NET_ERROR_PAGE_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/error_page/renderer/net_error_helper_core.h"
@@ skipping 36 matching lines @@
   static void Install(content::RenderFrame* render_frame,
                       base::WeakPtr<Delegate> delegate);
 
  private:
   explicit NetErrorPageController(base::WeakPtr<Delegate> delegate);
   ~NetErrorPageController() override;
 
   // Execute a "Show saved copy" button click.
   bool ShowSavedCopyButtonClick();
 
-  // Execute a "Show saved pages" button click.
-  bool ShowSavedPagesButtonClick();
+  // Execute a button click to show the list of all offline pages.
+  bool ShowOfflinePagesButtonClick();
+
+  // Execute a button click to show the offline copy of this page.
+  bool ShowOfflineCopyButtonClick();
 
   // Execute a "Reload" button click.
   bool ReloadButtonClick();
 
   // Execute a "Details" button click.
   bool DetailsButtonClick();
 
   // Track easter egg plays.
   bool TrackEasterEgg();
 
@@ skipping 13 matching lines @@
   // gin::WrappableBase
   gin::ObjectTemplateBuilder GetObjectTemplateBuilder(
       v8::Isolate* isolate) override;
 
   base::WeakPtr<Delegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(NetErrorPageController);
 };
 
 #endif  // CHROME_RENDERER_NET_NET_ERROR_PAGE_CONTROLLER_H_