Avoid patching in dart2dart.

pkg/analyzer2dart/lib/src/modely.dart

 // Copyright (c) 2014, 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.
 
 part of analyzer2dart.element_converter;
 
 
 /// Base [dart2js.Element] implementation for converted analyzer elements.
 class ElementY extends dart2js.Element {
   final ElementConverter converter;
@@ skipping 122 matching lines @@
   @override
   bool get isConst => unsupported('isConst');
 
   @override
   bool get isDeferredLoaderGetter => unsupported('isDeferredLoaderGetter');
 
   @override
   bool get isFactoryConstructor => unsupported('isFactoryConstructor');
 
   @override
-  bool get isForwardingConstructor => unsupported('isForwardingConstructor');
-
-  @override
   bool get isInjected => unsupported('isInjected');
 
   @override
   bool get isInstanceMember => unsupported('isInstanceMember');
 
   @override
   bool get isMixinApplication => unsupported('isMixinApplication');
 
   @override
   bool get isNative => unsupported('isNative');
@@ skipping 184 matching lines @@
     return false;
   }
 
   // TODO(johnniwinther): Ensure the correct semantics of this.
   @override
   bool get isAbstract => false;
 }
 
 abstract class FunctionElementMixin
     implements ElementY, dart2js.FunctionElement {
+
+  // TODO(johnniwinther): Ensure the correct semantics of this.
+  @override
+  bool get isExternal => false;
+
   @override
   get abstractField => unsupported('abstractField');
 
   @override
   computeSignature(_) => unsupported('computeSignature');
 
   @override
   get memberContext => unsupported('memberContext');
 
   @override
@@ skipping 419 matching lines @@
 
   @override
   bool get isRedirectingFactory => unsupported('isRedirectingFactory');
 
   @override
   get nestedClosures => unsupported('nestedClosures');
 
   @override
   get type => unsupported('type');
 }