Move remaining helpers to BackendHelpers

pkg/compiler/lib/src/js_emitter/native_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.
 
 part of dart2js.js_emitter;
 
 class NativeEmitter {
 
   // TODO(floitsch): the native-emitter should not know about ClassBuilders.
   final Map<Element, full_js_emitter.ClassBuilder> cachedBuilders;
@@ skipping 16 matching lines @@
       : this.emitterTask = emitterTask,
         subtypes = new Map<ClassElement, List<ClassElement>>(),
         directSubtypes = new Map<ClassElement, List<ClassElement>>(),
         nativeMethods = new Set<FunctionElement>(),
         cachedBuilders = emitterTask.compiler.cacheStrategy.newMap();
 
   Compiler get compiler => emitterTask.compiler;
 
   JavaScriptBackend get backend => compiler.backend;
 
+  BackendHelpers get helpers => backend.helpers;
+
   jsAst.Expression get defPropFunction {
-    Element element = backend.findHelper('defineProperty');
+    Element element = helpers.defineProperty;
     return emitterTask.staticFunctionAccess(element);
   }
 
   /**
    * Prepares native classes for emission. Returns the unneeded classes.
    *
    * Removes trivial classes (that can be represented by a super type) and
    * generates properties that have to be added to classes (native or not).
    *
    * Updates the `nativeLeafTags`, `nativeNonLeafTags` and `nativeExtensions`
@@ skipping 34 matching lines @@
     Set<Class> seen = new Set<Class>();
 
     Class objectClass = null;
     Class jsInterceptorClass = null;
 
     void walk(Class cls) {
       if (cls.element == compiler.coreClasses.objectClass) {
         objectClass = cls;
         return;
       }
-      if (cls.element == backend.jsInterceptorClass) {
+      if (cls.element == helpers.jsInterceptorClass) {
         jsInterceptorClass = cls;
         return;
       }
       if (seen.contains(cls)) return;
       seen.add(cls);
       walk(cls.superclass);
       preOrder.add(cls);
     }
     classes.forEach(walk);
 
@@ skipping 151 matching lines @@
         cls.callStubs.isEmpty &&
         !cls.superclass.isMixinApplication &&
         !cls.fields.any(needsAccessor);
   }
 
   void potentiallyConvertDartClosuresToJs(
       List<jsAst.Statement> statements,
       FunctionElement member,
       List<jsAst.Parameter> stubParameters) {
     FunctionSignature parameters = member.functionSignature;
-    Element converter = backend.findHelper('convertDartClosureToJS');
+    Element converter = helpers.closureConverter;
     jsAst.Expression closureConverter =
         emitterTask.staticFunctionAccess(converter);
     parameters.forEachParameter((ParameterElement parameter) {
       String name = parameter.name;
       // If [name] is not in [stubParameters], then the parameter is an optional
       // parameter that was not provided for this stub.
       for (jsAst.Parameter stubParameter in stubParameters) {
         if (stubParameter.name == name) {
           DartType type = parameter.type.unaliased;
           if (type is FunctionType) {
@@ skipping 81 matching lines @@
     // used.  We should also use an interceptor if the check can't be satisfied
     // by a native class in case we get a native instance that tries to spoof
     // the type info.  i.e the criteria for whether or not to use an interceptor
     // is whether the receiver can be native, not the type of the test.
     if (element == null || !element.isClass) return false;
     ClassElement cls = element;
     if (backend.isNativeOrExtendsNative(cls)) return true;
     return isSupertypeOfNativeClass(element);
   }
 }