[inspector] use own version of third_party/inspector_protocol

third_party/inspector_protocol/lib/BackendCallback_h.template

 // Copyright (c) 2016 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 {{"_".join(config.protocol.namespace)}}_BackendCallback_h
 #define {{"_".join(config.protocol.namespace)}}_BackendCallback_h
 
 //#include "Forward.h"
 
 {% for namespace in config.protocol.namespace %}
 namespace {{namespace}} {
 {% endfor %}
 
 class {{config.lib.export_macro}} BackendCallback {
 public:
     virtual ~BackendCallback() { }
     virtual void sendFailure(const ErrorString&) = 0;
 };
 
 {% for namespace in config.protocol.namespace %}
 } // namespace {{namespace}}
 {% endfor %}
 
 #endif // !defined({{"_".join(config.protocol.namespace)}}_BackendCallback_h)