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

runtime/vm/virtual_memory_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.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "vm/virtual_memory.h"
 
+#include <magenta/process.h>
 #include <magenta/status.h>
 #include <magenta/syscalls.h>
 #include <sys/mman.h>
 #include <unistd.h>
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 253 matching lines @@
     return false;
   }
   LOG_INFO("mx_vmar_protect(%lx, %lx, %x) success\n", page_address,
            end_address - page_address, prot);
   return true;
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)