Implement a Windows crash client registrar.

handler/handler.gyp

 # Copyright 2014 The Crashpad Authors. All rights reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 65 matching lines @@
           'type': 'static_library',
           'dependencies': [
              '../client/client.gyp:crashpad_client',
              '../third_party/mini_chromium/mini_chromium.gyp:base',
              '../util/util.gyp:crashpad_util',
           ],
           'include_dirs': [
             '..',
           ],
           'sources': [
+            'win/registrar.cc',
+            'win/registrar.h',
             'win/registration_pipe_state.cc',
             'win/registration_pipe_state.h',
             'win/registration_server.cc',
             'win/registration_server.h',
           ],
         },
       ],
     }, {
       'targets': [],
     }],
   ],
 }