Issue 3968. Report error if cycle in redirecting factory constructors

compiler/java/com/google/dart/compiler/resolver/SyntheticDefaultConstructorElement.java

 // Copyright (c) 2012, 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.
 package com.google.dart.compiler.resolver;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.dart.compiler.ast.DartMethodDefinition;
 import com.google.dart.compiler.type.FunctionType;
 import com.google.dart.compiler.type.Type;
 import com.google.dart.compiler.type.Types;
@@ skipping 68 matching lines @@
   public boolean hasBody() {
     return false;
   }
 
   @Override
   public ConstructorElement getDefaultConstructor() {
     return defaultConstructor;
   }
 
   @Override
+  public ConstructorElement getRedirectingFactoryConstructor() {
+    return null;
+  }
+
+  @Override
   public void setDefaultConstructor(ConstructorElement defaultConstructor) {
     this.defaultConstructor = defaultConstructor;
   }
 
   @Override
   public Type getReturnType() {
     return functionType.getReturnType();
   }
 
   @Override
@@ skipping 24 matching lines @@
   @Override
   public Element lookupLocalElement(String name) {
     return null;
   }
 
   @Override
   public Set<Element> getOverridden() {
     return ImmutableSet.of();
   }
 }