Issue 801. Use actual super constructor with all named or synthetic.

compiler/java/com/google/dart/compiler/backend/js/Normalizer.java

Index: compiler/java/com/google/dart/compiler/backend/js/Normalizer.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/Normalizer.java b/compiler/java/com/google/dart/compiler/backend/js/Normalizer.java
index 18947a9d5b8cc733ac2e3a07f31225e403fa512f..aca2528973da8e023849206dc7c7fb3058e2b6f3 100644
--- a/compiler/java/com/google/dart/compiler/backend/js/Normalizer.java
+++ b/compiler/java/com/google/dart/compiler/backend/js/Normalizer.java
@@ -737,8 +737,24 @@ public class Normalizer {
           if (superLocator.needsSuperInvocation) {
             DartSuperConstructorInvocation superInvocation = new DartSuperConstructorInvocation(
                 new DartIdentifier(""), Collections.<DartExpression>emptyList());
-            superInvocation.setSymbol(new SyntheticDefaultConstructorElement(null,
-                classElement.getSupertype().getElement(), null));
+            // Set constructor element - actual constructor with all named parameters or synthetic.
+            ConstructorElement superConstructorElement = null;
+            {
+              ClassElement superTypeElement = classElement.getSupertype().getElement();
+              List<ConstructorElement> constructors = superTypeElement.getConstructors();
+              for (ConstructorElement constructor : constructors) {
+                if (hasOnlyNamedParameters(constructor)) {
+                  superConstructorElement = constructor;
+                  break;
+                }
+              }
+              if (superConstructorElement == null) {
+                superConstructorElement =
+                    new SyntheticDefaultConstructorElement(null, superTypeElement, null);
+              }
+              superInvocation.setSymbol(superConstructorElement);
+            }
+            // Add implicit "super" invocation.
             nInit.add(new DartInitializer(null, superInvocation));
           }
         }
@@ -757,6 +773,18 @@ public class Normalizer {
       }
     }
 
+    /**
+     * @return <code>true</code> if given constructor has only named (i.e. optional) parameters.
+     */
+    private static boolean hasOnlyNamedParameters(ConstructorElement constructor) {
+      for (VariableElement parameter : constructor.getParameters()) {
+        if (!parameter.isNamed()) {
+          return false;
+        }
+      }
+      return true;
+    }
+
     private DartExpression normalizeCompoundAssignment(Token operator,
                                                        boolean isPostfix,
                                                        DartExpression operand1,