[Fuchsia] Use magenta/process.h for mx_job_default, mx_vmar_root_self

runtime/bin/process_fuchsia.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "bin/process.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <launchpad/launchpad.h>
 #include <launchpad/vmo.h>
+#include <magenta/process.h>
 #include <magenta/status.h>
 #include <magenta/syscalls.h>
 #include <magenta/syscalls/object.h>
 #include <mxio/util.h>
 #include <pthread.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/epoll.h>
@@ skipping 789 matching lines @@
 void Process::ClearSignalHandler(intptr_t signal) {
   UNIMPLEMENTED();
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)
 
 #endif  // !defined(DART_IO_DISABLED)