Remove the partially completed code for remote IsolateMirrors and

runtime/vm/dart_entry.h

 // Copyright (c) 2011, 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 VM_DART_ENTRY_H_
 #define VM_DART_ENTRY_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
@@ skipping 72 matching lines @@
 
   // map[key] = value;
   //
   // Returns null on success, a RawError on failure.
   static RawObject* MapSetAt(const Instance& map,
                              const Instance& key,
                              const Instance& value);
 
   // Gets the _id field of a SendPort/ReceivePort.
   //
-  // Returns null on success, a RawError on failure.
+  // Returns the value of _id on success, a RawError on failure.
   static RawObject* PortGetId(const Instance& port);
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_ENTRY_H_