Surface button for loading stale cache copy on net error page.

chrome/browser/net/net_error_tab_helper.h

 // Copyright (c) 2012 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_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
 #define CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 28 matching lines @@
 
   // Sets a callback that will be called immediately after the helper sends
   // a NetErrorHelper IPC.  (Used by the DNS probe browser test to know when to
   // check the error page for updates, instead of polling.)
   void set_dns_probe_status_snoop_callback_for_testing(
       const DnsProbeStatusSnoopCallback& dns_probe_status_snoop_callback) {
     dns_probe_status_snoop_callback_ = dns_probe_status_snoop_callback;
   }
 
   // content::WebContentsObserver implementation.
+  virtual void DidStartNavigationToPendingEntry(
+      const GURL& url,
+      content::NavigationController::ReloadType reload_type) OVERRIDE;
+
   virtual void DidStartProvisionalLoadForFrame(
       int64 frame_id,
       int64 parent_frame_id,
       bool is_main_frame,
       const GURL& validated_url,
       bool is_error_page,
       bool is_iframe_srcdoc,
       content::RenderViewHost* render_view_host) OVERRIDE;
 
   virtual void DidCommitProvisionalLoadForFrame(
@@ skipping 57 matching lines @@
   // "Use a web service to resolve navigation errors" preference is required
   // to allow probes.
   BooleanPrefMember resolve_errors_with_web_service_;
 
   DISALLOW_COPY_AND_ASSIGN(NetErrorTabHelper);
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_NET_ERROR_TAB_HELPER_H_