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

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/names.dart' show Identifiers;
 import '../compiler.dart' show Compiler;
 import '../diagnostics/messages.dart' show MessageKind;
@@ skipping 50 matching lines @@
   void processJsInteropAnnotation(Element e) {
     for (MetadataAnnotation annotation in e.implementation.metadata) {
       ConstantValue constant = backend.compiler.constants.getConstantValue(
           annotation.constant);
       if (constant == null || constant is! ConstructedConstantValue) continue;
       ConstructedConstantValue constructedConstant = constant;
       if (constructedConstant.type.element == backend.jsAnnotationClass) {
         ConstantValue value = constructedConstant.fields[nameField];
         if (value.isString) {
           StringConstantValue stringValue = value;
-          e.setJsInteropName(stringValue.primitiveValue.slowToString());
+          backend.setJsInteropName(
+              e, stringValue.primitiveValue.slowToString());
         } else {
           // TODO(jacobr): report a warning if the value is not a String.
-          e.setJsInteropName('');
+          backend.setJsInteropName(e, '');
         }
         enabledJsInterop = true;
         return;
       }
     }
   }
 
   void processJsInteropAnnotationsInLibrary(LibraryElement library) {
     processJsInteropAnnotation(library);
     library.implementation.forEachLocalMember((Element element) {
       processJsInteropAnnotation(element);
-      if (!element.isClass || !element.isJsInterop) return;
+      if (!element.isClass || !backend.isJsInterop(element)) return;
 
       ClassElement classElement = element;
 
       if (!classElement
           .implementsInterface(backend.jsJavaScriptObjectClass)) {
         backend.reporter.reportErrorMessage(classElement,
             MessageKind.JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS, {
           'cls': classElement.name,
           'superclass': classElement.superclass.name
         });
       }
 
       classElement.forEachMember(
           (ClassElement classElement, Element member) {
         processJsInteropAnnotation(member);
 
         if (!member.isSynthesized &&
-            classElement.isJsInterop &&
+            backend.isJsInterop(classElement) &&
             member is FunctionElement) {
           FunctionElement fn = member;
           if (!fn.isExternal && !fn.isAbstract) {
             backend.reporter.reportErrorMessage(
                 fn,
                 MessageKind.JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER,
                 {'cls': classElement.name, 'member': member.name});
           }
         }
       });
@@ skipping 18 matching lines @@
           var name = backend.namer.invocationName(selector);
           statements.add(js.statement(
               'Function.prototype.# = function(#) { return this(#) }',
               [name, parameters, parameters]));
         }
       });
     });
     return new jsAst.Block(statements);
   }
 }