Add Directory.systemTemp getter to replace createSystemTemp().

runtime/bin/builtin_natives.cc

 // Copyright (c) 2012, 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 <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "include/dart_api.h"
 
 #include "platform/assert.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/io_natives.h"
 #include "bin/platform.h"
 
 namespace dart {
 namespace bin {
 
 // Lists the native functions implementing basic functionality in
 // standalone dart, such as printing, file I/O, and platform information.
 // Advanced I/O classes like sockets and process management are implemented
 // using functions listed in io_natives.cc.
 #define BUILTIN_NATIVE_LIST(V)                                                 \
   V(Directory_Exists, 1)                                                       \
   V(Directory_Create, 1)                                                       \
   V(Directory_Current, 0)                                                      \
   V(Directory_SetCurrent, 1)                                                   \
-  V(Directory_CreateTemp, 2)                                                   \
+  V(Directory_SystemTemp, 0)                                                   \
+  V(Directory_CreateTemp, 1)                                                   \
   V(Directory_Delete, 2)                                                       \
   V(Directory_Rename, 2)                                                       \
   V(Directory_List, 3)                                                         \
   V(File_Open, 2)                                                              \
   V(File_Exists, 1)                                                            \
   V(File_Close, 1)                                                             \
   V(File_ReadByte, 1)                                                          \
   V(File_WriteByte, 2)                                                         \
   V(File_Read, 2)                                                              \
   V(File_ReadInto, 4)                                                          \
@@ skipping 69 matching lines @@
     // Dart_StringToUTF8?  We need to make sure not to swallow the
     // interrupt.
     Platform::PrintBlocking(stdout, "%s\n", Dart_GetError(result));
   } else {
     Platform::PrintBlocking(stdout, "%.*s\n", static_cast<int>(length), chars);
   }
 }
 
 }  // namespace bin
 }  // namespace dart