dart2js: Fix build.

pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart

 // 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.
 
 library dart2js.ir_builder_task;
 
 import '../closure.dart' as closure;
 import '../common.dart';
 import '../common/names.dart' show
     Names,
@@ skipping 2765 matching lines @@
           internalError(argument, 'Additional argument.');
         }
       }
       if (count < minimum) {
         internalError(node, 'Expected at least $minimum arguments.');
       }
     }
 
     /// Call a helper method from the isolate library. The isolate library uses
     /// its own isolate structure, that encapsulates dart2js's isolate.
-    ir.Primitive buildIsolateHelperInvocation(Element element,
+    ir.Primitive buildIsolateHelperInvocation(MethodElement element,
         CallStructure callStructure) {
       if (element == null) {
         reporter.internalError(node,
             'Isolate library and compiler mismatch.');
       }
       List<ir.Primitive> arguments = <ir.Primitive>[];
       callStructure = translateStaticArguments(argumentList, element,
           callStructure, arguments);
       Selector selector = new Selector.call(element.memberName, callStructure);
       return irBuilder.buildInvokeStatic(element, selector, arguments,
@@ skipping 816 matching lines @@
   }
 
   Element get closureConverter {
     return _backend.helpers.closureConverter;
   }
 
   void addNativeMethod(FunctionElement function) {
     _backend.emitter.nativeEmitter.nativeMethods.add(function);
   }
 }