Add support for native ports in the vm.

runtime/vm/dart_api_impl.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_API_IMPL_H_
 #define VM_DART_API_IMPL_H_
 
 #include "vm/allocation.h"
 #include "vm/object.h"
 
@@ skipping 105 matching lines @@
   // Gets a handle to False
   static Dart_Handle False();
 
   // Allocates space in the local zone.
   static uword Allocate(intptr_t size);
 
   // Reallocates space in the local zone.
   static uword Reallocate(uword ptr, intptr_t old_size, intptr_t new_size);
 };
 
+class IsolateSaver {
+ public:
+  explicit IsolateSaver(Isolate* current_isolate)
+      : saved_isolate_(current_isolate) {
+  }
+  ~IsolateSaver() {
+    Isolate::SetCurrent(saved_isolate_);
+  }
+ private:
+  Isolate* saved_isolate_;
+
+  DISALLOW_COPY_AND_ASSIGN(IsolateSaver);
+};
+
 }  // namespace dart.
 
 #endif  // VM_DART_API_IMPL_H_