Use the correct null constants for Mach threads, tasks, and hosts

util/mach/exc_server_variants.cc

 // 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 497 matching lines @@
     const exception_data_type_t* code,
     mach_msg_type_number_t code_count,
     thread_state_flavor_t* flavor,
     const natural_t* old_state,
     mach_msg_type_number_t old_state_count,
     thread_state_t new_state,
     mach_msg_type_number_t* new_state_count) {
   bool destroy_complex_request = false;
   return interface_->CatchException(EXCEPTION_STATE,
                                     exception_port,
-                                    MACH_PORT_NULL,
-                                    MACH_PORT_NULL,
+                                    THREAD_NULL,
+                                    TASK_NULL,
                                     exception,
                                     code,
                                     code_count,
                                     flavor,
                                     old_state,
                                     old_state_count,
                                     new_state,
                                     new_state_count,
                                     &destroy_complex_request);
 }
@@ skipping 65 matching lines @@
     const mach_exception_data_type_t* code,
     mach_msg_type_number_t code_count,
     thread_state_flavor_t* flavor,
     const natural_t* old_state,
     mach_msg_type_number_t old_state_count,
     thread_state_t new_state,
     mach_msg_type_number_t* new_state_count) {
   bool destroy_complex_request = false;
   return interface_->CatchMachException(EXCEPTION_STATE | MACH_EXCEPTION_CODES,
                                         exception_port,
-                                        MACH_PORT_NULL,
-                                        MACH_PORT_NULL,
+                                        THREAD_NULL,
+                                        TASK_NULL,
                                         exception,
                                         code,
                                         code_count,
                                         flavor,
                                         old_state,
                                         old_state_count,
                                         new_state,
                                         new_state_count,
                                         &destroy_complex_request);
 }
@@ skipping 136 matching lines @@
 kern_return_t ExcServerSuccessfulReturnValue(exception_behavior_t behavior,
                                              bool set_thread_state) {
   if (!set_thread_state && ExceptionBehaviorHasState(behavior)) {
     return MACH_RCV_PORT_DIED;
   }
 
   return KERN_SUCCESS;
 }
 
 }  // namespace crashpad