Revert "Compute frontend/backend specific constants."

sdk/lib/_internal/compiler/implementation/js_emitter/interceptor_emitter.dart

 // Copyright (c) 2013, 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;
 
 class InterceptorEmitter extends CodeEmitterHelper {
   final Set<String> interceptorInvocationNames = new Set<String>();
 
   void recordMangledNameOfMemberMethod(FunctionElement member, String name) {
     if (backend.isInterceptedMethod(member)) {
       interceptorInvocationNames.add(name);
     }
   }
 
   Set<ClassElement> interceptorsReferencedFromConstants() {
     Set<ClassElement> classes = new Set<ClassElement>();
-    JavaScriptConstantCompiler handler = backend.constants;
+    ConstantHandler handler = compiler.constantHandler;
     List<Constant> constants = handler.getConstantsForEmission();
     for (Constant constant in constants) {
       if (constant is InterceptorConstant) {
         InterceptorConstant interceptorConstant = constant;
         classes.add(interceptorConstant.dispatchedType.element);
       }
     }
     return classes;
   }
 
@@ skipping 406 matching lines @@
    * Emit initializer for [mapTypeToInterceptor] data structure used by
    * [findInterceptorForType].  See declaration of [mapTypeToInterceptor] in
    * `interceptors.dart`.
    */
   void emitMapTypeToInterceptor(CodeBuffer buffer) {
     // TODO(sra): Perhaps inject a constant instead?
     CustomElementsAnalysis analysis = backend.customElementsAnalysis;
     if (!analysis.needsTable) return;
 
     List<jsAst.Expression> elements = <jsAst.Expression>[];
-    JavaScriptConstantCompiler handler = backend.constants;
+    ConstantHandler handler = compiler.constantHandler;
     List<Constant> constants =
         handler.getConstantsForEmission(task.compareConstants);
     for (Constant constant in constants) {
       if (constant is TypeConstant) {
         TypeConstant typeConstant = constant;
         Element element = typeConstant.representedType.element;
         if (element is ClassElement) {
           ClassElement classElement = element;
           if (!analysis.needsClass(classElement)) continue;
 
@@ skipping 33 matching lines @@
     jsAst.ArrayInitializer array = new jsAst.ArrayInitializer.from(elements);
     String name =
         backend.namer.getNameOfGlobalField(backend.mapTypeToInterceptor);
     jsAst.Expression assignment =
         js('${task.isolateProperties}.$name = #', array);
 
     buffer.write(jsAst.prettyPrint(assignment, compiler));
     buffer.write(N);
   }
 }