Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/js_backend/constant_emitter.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.
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../io/code_output.dart';
@@ skipping 253 matching lines @@
   JavaScriptBackend get backend => compiler.backend;
 
   jsAst.PropertyAccess getHelperProperty(MethodElement helper) {
     return backend.emitter.staticFunctionAccess(helper);
   }
 
   @override
   jsAst.Expression visitType(TypeConstantValue constant, [_]) {
     ResolutionDartType type = constant.representedType;
     jsAst.Name typeName = namer.runtimeTypeName(type.element);
-    return new jsAst.Call(getHelperProperty(backend.helpers.createRuntimeType),
+    return new jsAst.Call(
+        getHelperProperty(backend.commonElements.createRuntimeType),
         [js.quoteName(typeName)]);
   }
 
   @override
   jsAst.Expression visitInterceptor(InterceptorConstantValue constant, [_]) {
     ClassElement interceptorClass = constant.cls;
     return backend.emitter.interceptorPrototypeAccess(interceptorClass);
   }
 
   @override
@@ skipping 36 matching lines @@
   String stripComments(String rawJavaScript) {
     return rawJavaScript.replaceAll(COMMENT_RE, '');
   }
 
   jsAst.Expression maybeAddTypeArguments(
       ResolutionInterfaceType type, jsAst.Expression value) {
     if (type is ResolutionInterfaceType &&
         !type.treatAsRaw &&
         backend.rtiNeed.classNeedsRti(type.element)) {
       return new jsAst.Call(
-          getHelperProperty(backend.helpers.setRuntimeTypeInfo),
+          getHelperProperty(backend.commonElements.setRuntimeTypeInfo),
           [value, _reifiedTypeArguments(type)]);
     }
     return value;
   }
 
   jsAst.Expression _reifiedTypeArguments(ResolutionInterfaceType type) {
     jsAst.Expression unexpected(ResolutionTypeVariableType variable) {
       reporter.internalError(
           NO_LOCATION_SPANNABLE,
           "Unexpected type variable '${variable.getStringAsDeclared(null)}'"
           " in constant type '${type.getStringAsDeclared(null)}'");
       return null;
     }
 
     List<jsAst.Expression> arguments = <jsAst.Expression>[];
     RuntimeTypesEncoder rtiEncoder = backend.rtiEncoder;
     for (ResolutionDartType argument in type.typeArguments) {
       arguments.add(rtiEncoder.getTypeRepresentation(argument, unexpected));
     }
     return new jsAst.ArrayInitializer(arguments);
   }
 
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }