Issue 3968. Report error if cycle in redirecting factory constructors

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

Index: compiler/java/com/google/dart/compiler/resolver/ConstructorElementImplementation.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/ConstructorElementImplementation.java b/compiler/java/com/google/dart/compiler/resolver/ConstructorElementImplementation.java
index 227f7dbd763fd55e9e08cb0a146e63a5f375ef6a..227daaee45ff7ac58e1387a1ee2d0d5830ac25b2 100644
--- a/compiler/java/com/google/dart/compiler/resolver/ConstructorElementImplementation.java
+++ b/compiler/java/com/google/dart/compiler/resolver/ConstructorElementImplementation.java
@@ -15,6 +15,7 @@ class ConstructorElementImplementation extends MethodElementImplementation
   private final ClassElement constructorType;
   private final String rawName;
   private ConstructorElement defaultConstructor;
+  private ConstructorElement redirectingFactoryConstructor;
 
   private ConstructorElementImplementation(DartMethodDefinition node,
                              String name,
@@ -75,6 +76,15 @@ class ConstructorElementImplementation extends MethodElementImplementation
     this.defaultConstructor = defaultConstructor;
   }
 
+  @Override
+  public ConstructorElement getRedirectingFactoryConstructor() {
+    return redirectingFactoryConstructor;
+  }
+  
+  public void setRedirectingFactoryConstructor(ConstructorElement redirectingFactoryConstructor) {
+    this.redirectingFactoryConstructor = redirectingFactoryConstructor;
+  }
+
   public static ConstructorElementImplementation fromMethodNode(DartMethodDefinition node,
                                                   String name,
                                                   ClassElement declaringClass,