Mark Foreign as builtin.

pkg/fletchc/lib/src/fletch_backend.dart

 // Copyright (c) 2015, the Fletch 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.md file.
 
 library fletchc.fletch_backend;
 
 import 'dart:async' show
     Future;
 
 import 'package:compiler/src/dart2jslib.dart' show
@@ skipping 350 matching lines @@
     mintClass = loadBuiltinClass("_Mint", fletchSystemLibrary).element;
     stringClass = loadBuiltinClass("String", fletchSystemLibrary).element;
     // TODO(ahe): Register _ConstantList through ResolutionCallbacks.
     loadBuiltinClass(constantListName, fletchSystemLibrary);
     loadBuiltinClass(constantMapName, fletchSystemLibrary);
     loadBuiltinClass("double", fletchSystemLibrary);
     loadBuiltinClass("Null", compiler.coreLibrary);
     loadBuiltinClass("bool", compiler.coreLibrary);
     loadBuiltinClass("Coroutine", compiler.coreLibrary);
     loadBuiltinClass("Port", compiler.coreLibrary);
+    loadBuiltinClass("Foreign", fletchFFILibrary);
 
     growableListClass =
         loadClass(growableListName, fletchSystemLibrary).element;
     linkedHashMapClass =
         loadClass(linkedHashMapName, fletchSystemLibrary).element;
     // Register list constructors to world.
     // TODO(ahe): Register growableListClass through ResolutionCallbacks.
     growableListClass.constructors.forEach(world.registerStaticUse);
     linkedHashMapClass.constructors.forEach(world.registerStaticUse);
 
@@ skipping 793 matching lines @@
     compiler.reportError(
         spannable, MessageKind.GENERIC, {'text': reason});
     var constString = constantSystem.createString(
         new DartString.literal(reason));
     context.markConstantUsed(constString);
     function
         ..builder.loadConst(function.allocateConstant(constString))
         ..builder.emitThrow();
   }
 }