Use elements/types in constants/values

pkg/compiler/lib/src/js_emitter/program_builder/collector.dart

 // Copyright (c) 2015, 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.js_emitter.program_builder;
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
@@ skipping 39 matching lines @@
   Collector(this.compiler, this.namer, this.closedWorld, this.rtiNeededClasses,
       this.emitter);
 
   Set<ClassElement> computeInterceptorsReferencedFromConstants() {
     Set<ClassElement> classes = new Set<ClassElement>();
     JavaScriptConstantCompiler handler = backend.constants;
     List<ConstantValue> constants = handler.getConstantsForEmission();
     for (ConstantValue constant in constants) {
       if (constant is InterceptorConstantValue) {
         InterceptorConstantValue interceptorConstant = constant;
-        classes.add(interceptorConstant.dispatchedType.element);
+        classes.add(interceptorConstant.cls);
       }
     }
     return classes;
   }
 
   /**
    * Return a function that returns true if its argument is a class
    * that needs to be emitted.
    */
   Function computeClassFilter() {
@@ skipping 246 matching lines @@
   }
 
   void collect() {
     computeNeededDeclarations();
     computeNeededConstants();
     computeNeededStatics();
     computeNeededStaticNonFinalFields();
     computeNeededLibraries();
   }
 }