Set the chromium_code GYP variable

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,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'conditions': [
     ['OS=="mac"', {
       'targets': [
         {
           'target_name': 'crashpad_handler',
           'type': 'executable',
           'dependencies': [
             '../client/client.gyp:client',
             '../compat/compat.gyp:compat',
             '../minidump/minidump.gyp:minidump',
@@ skipping 14 matching lines @@
             'mac/exception_handler_server.h',
             'mac/main.cc',
           ],
         },
       ],
     }, {
       'targets': [],
     }],
   ],
 }