Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/js_backend/js_interop_analysis.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.
 
 /// Analysis to determine how to generate code for typed JavaScript interop.
 library compiler.src.js_backend.js_interop_analysis;
 
 import '../common.dart';
 import '../constants/values.dart'
     show ConstantValue, ConstructedConstantValue, StringConstantValue;
 import '../elements/resolution_types.dart'
     show ResolutionDartType, ResolutionDynamicType, ResolutionFunctionType;
 import '../diagnostics/messages.dart' show MessageKind;
 import '../elements/elements.dart'
     show
         ClassElement,
         Element,
         FieldElement,
         LibraryElement,
         ParameterElement,
         MemberElement,
         MethodElement,
         MetadataAnnotation;
 import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../universe/selector.dart' show Selector;
 import '../universe/world_builder.dart' show SelectorConstraints;
-import 'backend_helpers.dart' show BackendHelpers;
 import 'js_backend.dart' show JavaScriptBackend;
 
 class JsInteropAnalysis {
   final JavaScriptBackend backend;
 
   /// The resolved [FieldElement] for `Js.name`.
   FieldElement nameField;
   bool enabledJsInterop = false;
 
   /// Whether the backend is currently processing the codegen queue.
   bool _inCodegen = false;
 
   JsInteropAnalysis(this.backend);
 
-  BackendHelpers get helpers => backend.helpers;
-
   void onQueueClosed() {
     if (_inCodegen) return;
 
-    if (helpers.jsAnnotationClass != null) {
-      ClassElement cls = helpers.jsAnnotationClass;
+    if (backend.compiler.commonElements.jsAnnotationClass != null) {
+      ClassElement cls = backend.compiler.commonElements.jsAnnotationClass;
       nameField = cls.lookupMember('name');
       backend.compiler.libraryLoader.libraries
           .forEach(processJsInteropAnnotationsInLibrary);
     }
   }
 
   void onCodegenStart() {
     _inCodegen = true;
   }
 
   /// Resolves the metadata of [element] and returns the name of the `JS(...)`
   /// annotation for js interop, if found.
   String processJsInteropAnnotation(Element element) {
     for (MetadataAnnotation annotation in element.implementation.metadata) {
       // TODO(johnniwinther): Avoid processing unresolved elements.
       if (annotation.constant == null) continue;
       ConstantValue constant =
           backend.compiler.constants.getConstantValue(annotation.constant);
       if (constant == null || constant is! ConstructedConstantValue) continue;
       ConstructedConstantValue constructedConstant = constant;
-      if (constructedConstant.type.element == helpers.jsAnnotationClass) {
+      if (constructedConstant.type.element ==
+          backend.compiler.commonElements.jsAnnotationClass) {
         ConstantValue value = constructedConstant.fields[nameField];
         String name;
         if (value.isString) {
           StringConstantValue stringValue = value;
           name = stringValue.primitiveValue.slowToString();
         } else {
           // TODO(jacobr): report a warning if the value is not a String.
           name = '';
         }
         enabledJsInterop = true;
         return name;
       }
     }
     return null;
   }
 
   bool hasAnonymousAnnotation(Element element) {
-    if (backend.helpers.jsAnonymousClass == null) return false;
+    if (backend.compiler.commonElements.jsAnonymousClass == null) return false;
     return element.metadata.any((MetadataAnnotation annotation) {
       ConstantValue constant =
           backend.compiler.constants.getConstantValue(annotation.constant);
       if (constant == null || constant is! ConstructedConstantValue)
         return false;
       ConstructedConstantValue constructedConstant = constant;
       return constructedConstant.type.element ==
-          backend.helpers.jsAnonymousClass;
+          backend.compiler.commonElements.jsAnonymousClass;
     });
   }
 
   void _checkFunctionParameters(MethodElement fn) {
     if (fn.hasFunctionSignature &&
         fn.functionSignature.optionalParametersAreNamed) {
       backend.reporter.reportErrorMessage(
           fn,
           MessageKind.JS_INTEROP_METHOD_WITH_NAMED_ARGUMENTS,
           {'method': fn.name});
@@ skipping 28 matching lines @@
       }
       if (!backend.nativeData.isJsInteropClass(classElement)) return;
 
       // Skip classes that are completely unreachable. This should only happen
       // when all of jsinterop types are unreachable from main.
       if (!backend.compiler.resolutionWorldBuilder
           .isImplemented(classElement)) {
         return;
       }
 
-      if (!classElement.implementsInterface(helpers.jsJavaScriptObjectClass)) {
+      if (!classElement.implementsInterface(
+          backend.compiler.commonElements.jsJavaScriptObjectClass)) {
         backend.reporter.reportErrorMessage(classElement,
             MessageKind.JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS, {
           'cls': classElement.name,
           'superclass': classElement.superclass.name
         });
       }
 
       classElement
           .forEachMember((ClassElement classElement, MemberElement member) {
         String memberName = processJsInteropAnnotation(member);
@@ skipping 62 matching lines @@
   ResolutionFunctionType buildJsFunctionType() {
     // TODO(jacobr): consider using codegenWorldBuilder.isChecks to determine the
     // range of positional arguments that need to be supported by JavaScript
     // function types.
     return new ResolutionFunctionType.synthesized(
         const ResolutionDynamicType(),
         [],
         new List<ResolutionDartType>.filled(16, const ResolutionDynamicType()));
   }
 }