Move native and js interop properties from the element model to the JS backend

pkg/compiler/lib/src/js_backend/custom_elements_analysis.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 js_backend;
 
 /**
  * Support for Custom Elements.
  *
  * The support for custom elements the compiler builds a table that maps the
@@ skipping 50 matching lines @@
     // TODO(12607): Match on [ClassMirror.reflectedType]
     resolutionJoin.allClassesSelected = true;
     codegenJoin.allClassesSelected = true;
   }
 
   CustomElementsAnalysisJoin joinFor(Enqueuer enqueuer) =>
       enqueuer.isResolutionQueue ? resolutionJoin : codegenJoin;
 
   void registerInstantiatedClass(ClassElement classElement, Enqueuer enqueuer) {
     classElement.ensureResolved(compiler.resolution);
-    if (!Elements.isNativeOrExtendsNative(classElement)) return;
+    if (!backend.isNativeOrExtendsNative(classElement)) return;
     if (classElement.isMixinApplication) return;
     if (classElement.isAbstract) return;
     // JsInterop classes are opaque interfaces without a concrete
     // implementation.
-    if (classElement.isJsInterop) return;
+    if (backend.isJsInterop(classElement)) return;
     joinFor(enqueuer).instantiatedClasses.add(classElement);
   }
 
   void registerTypeLiteral(DartType type) {
     if (type.isInterfaceType) {
       // TODO(sra): If we had a flow query from the type literal expression to
       // the Type argument of the metadata lookup, we could tell if this type
       // literal is really a demand for the metadata.
       resolutionJoin.selectedClasses.add(type.element);
     } else if (type.isTypeVariable) {
@@ skipping 55 matching lines @@
 
   // ClassesOutput: classes requiring metadata.
   final activeClasses = new Set<ClassElement>();
 
   CustomElementsAnalysisJoin(this.backend);
 
   void flush(Enqueuer enqueuer) {
     if (!demanded) return;
     var newActiveClasses = new Set<ClassElement>();
     for (ClassElement classElement in instantiatedClasses) {
-      bool isNative = classElement.isNative;
+      bool isNative = backend.isNative(classElement);
       bool isExtension =
-          !isNative && Elements.isNativeOrExtendsNative(classElement);
+          !isNative && backend.isNativeOrExtendsNative(classElement);
       // Generate table entries for native classes that are explicitly named and
       // extensions that fix our criteria.
       if ((isNative && selectedClasses.contains(classElement)) ||
           (isExtension &&
               (allClassesSelected || selectedClasses.contains(classElement)))) {
         newActiveClasses.add(classElement);
         Iterable<Element> escapingConstructors =
             computeEscapingConstructors(classElement);
         escapingConstructors.forEach(enqueuer.registerStaticUse);
         escapingConstructors
@@ skipping 12 matching lines @@
   TypeConstantValue makeTypeConstant(ClassElement element) {
     DartType elementType = element.rawType;
     return backend.constantSystem.createType(compiler, elementType);
   }
 
   List<Element> computeEscapingConstructors(ClassElement classElement) {
     List<Element> result = <Element>[];
     // Only classes that extend native classes have constructors in the table.
     // We could refine this to classes that extend Element, but that would break
     // the tests and there is no sane reason to subclass other native classes.
-    if (classElement.isNative) return result;
+    if (backend.isNative(classElement)) return result;
 
     selectGenerativeConstructors(ClassElement enclosing, Element member) {
       if (member.isGenerativeConstructor) {
         // Ignore constructors that cannot be called with zero arguments.
         FunctionElement constructor = member;
         constructor.computeType(compiler.resolution);
         FunctionSignature parameters = constructor.functionSignature;
         if (parameters.requiredParameterCount == 0) {
           result.add(member);
         }
       }
     }
     classElement.forEachMember(selectGenerativeConstructors,
         includeBackendMembers: false,
         includeSuperAndInjectedMembers: false);
     return result;
   }
 }