Remove support for interface in dart2js.

sdk/lib/_internal/compiler/implementation/compile_time_constants.dart

 // 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.
 
 part of dart2js;
 
 /**
  * The [ConstantHandler] keeps track of compile-time constants,
  * initializations of global and static fields, and default values of
  * optional parameters.
@@ skipping 629 matching lines @@
 
   Constant visitNewExpression(NewExpression node) {
     if (!node.isConst()) {
       return signalNotCompileTimeConstant(node);
     }
 
     Send send = node.send;
     FunctionElement constructor = elements[send];
     constructor = constructor.redirectionTarget;
     ClassElement classElement = constructor.getEnclosingClass();
-    if (classElement.isInterface()) {
-      compiler.resolver.resolveMethodElement(constructor);
-      constructor = constructor.defaultImplementation;
-      classElement = constructor.getEnclosingClass();
-    }
     // The constructor must be an implementation to ensure that field
     // initializers are handled correctly.
     constructor = constructor.implementation;
     assert(invariant(node, constructor.isImplementation));
 
     Selector selector = elements.getSelector(send);
     List<Constant> arguments = evaluateArgumentsToConstructor(
         node, selector, send.arguments, constructor);
     ConstructorEvaluator evaluator =
         new ConstructorEvaluator(node, constructor, handler, compiler);
@@ skipping 222 matching lines @@
             // Use the default value.
             fieldValue = handler.compileConstant(field);
           }
           jsNewArguments.add(fieldValue);
         },
         includeBackendMembers: true,
         includeSuperMembers: true);
     return jsNewArguments;
   }
 }