Refactor multiprocess test code to allow multiple child processes to be launched.

test/test.gyp

 # Copyright 2015 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 33 matching lines @@
         'multiprocess_exec_win.cc',
         'multiprocess_posix.cc',
         'paths.cc',
         'paths.h',
         'paths_mac.cc',
         'paths_win.cc',
         'scoped_temp_dir.cc',
         'scoped_temp_dir.h',
         'scoped_temp_dir_posix.cc',
         'scoped_temp_dir_win.cc',
+        'win/win_child_process.cc',
+        'win/win_child_process.h',
         'win/win_multiprocess.cc',
         'win/win_multiprocess.h',
       ],
       'conditions': [
         ['OS=="mac"', {
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/usr/lib/libbsm.dylib',
             ],
           },
         }],
         ['OS=="win"', {
           'link_settings': {
             'libraries': [
               '-lshell32.lib',
             ],
           },
         }],
       ],
     },
   ],
 }