mac: Make UseSystemDefaultHandler() clear handlers on failure

client/crashpad_client_mac.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 203 matching lines @@
   return exception_port_ ? true : false;
 }
 
 bool CrashpadClient::UseHandler() {
   DCHECK_NE(exception_port_, kMachPortNull);
 
   return SetCrashExceptionPorts(exception_port_);
 }
 
 // static
-bool CrashpadClient::UseSystemDefaultHandler() {
+void CrashpadClient::UseSystemDefaultHandler() {
   base::mac::ScopedMachSendRight
       system_crash_reporter_handler(SystemCrashReporterHandler());
 
   // Proceed even if SystemCrashReporterHandler() failed, setting MACH_PORT_NULL
   // to clear the current exception ports.
-  return SetCrashExceptionPorts(system_crash_reporter_handler);
+  if (!SetCrashExceptionPorts(system_crash_reporter_handler)) {
+    SetCrashExceptionPorts(MACH_PORT_NULL);
+  }
 }
 
 }  // namespace crashpad