Really remove io support when dart:io is unsupported.

runtime/bin/io_service.h

 // Copyright (c) 2013, 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.
 
 #ifndef BIN_IO_SERVICE_H_
 #define BIN_IO_SERVICE_H_
 
+#if defined(DART_IO_DISABLED) || defined(DART_IO_SECURE_SOCKET_DISABLED)
+#error "io_service.h can only be included on builds with IO and SSL enabled"
+#endif
+
 #include "bin/builtin.h"
 #include "bin/utils.h"
 
 namespace dart {
 namespace bin {
 
 // This list must be kept in sync with the list in sdk/lib/io/io_service.dart
 #define IO_SERVICE_REQUEST_LIST(V)                                             \
   V(File, Exists, 0)                                                           \
   V(File, Create, 1)                                                           \
@@ skipping 49 matching lines @@
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(IOService);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_IO_SERVICE_H_