Fix headless_browsertests failures with PlzNavigate.

content/browser/devtools/protocol/network_handler.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 CONTENT_BROWSER_DEVTOOLS_PROTOCOL_NETWORK_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_NETWORK_HANDLER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 53 matching lines @@
   void NavigationPreloadRequestSent(int worker_version_id,
                                     const std::string& request_id,
                                     const ResourceRequest& request);
   void NavigationPreloadResponseReceived(int worker_version_id,
                                          const std::string& request_id,
                                          const GURL& url,
                                          const ResourceResponseHead& head);
   void NavigationPreloadCompleted(
       const std::string& request_id,
       const ResourceRequestCompletionStatus& completion_status);
+  void NavigationFailed(const std::string& request_id,
+                        const std::string& error_string,
+                        bool cancelled);
 
   bool enabled() const { return enabled_; }
   std::string UserAgentOverride() const;
 
  private:
   std::unique_ptr<Network::Frontend> frontend_;
   RenderFrameHostImpl* host_;
   bool enabled_;
   std::string user_agent_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_NETWORK_HANDLER_H_