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

pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart

 // Copyright (c) 2014, 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 InterceptorStubGenerator {
   final Compiler compiler;
   final Namer namer;
   final JavaScriptBackend backend;
@@ skipping 61 matching lines @@
         // The set of classes includes classes mixed-in to interceptor classes
         // and user extensions of native classes.
         //
         // The set of classes also includes the 'primitive' interceptor
         // PlainJavaScriptObject even when it has not been resolved, since it is
         // only resolved through the reference in getNativeInterceptor when
         // getNativeInterceptor is marked as used.  Guard against probing
         // unresolved PlainJavaScriptObject by testing for anyNativeClasses.
 
         if (anyNativeClasses) {
-          if (Elements.isNativeOrExtendsNative(cls)) hasNative = true;
+          if (backend.isNativeOrExtendsNative(cls)) hasNative = true;
         }
       }
     }
     if (hasDouble) {
       hasNumber = true;
     }
     if (hasInt) hasNumber = true;
 
     if (classes.containsAll(backend.interceptedClasses)) {
       // I.e. this is the general interceptor.
@@ skipping 274 matching lines @@
 
           var map = new jsAst.ObjectInitializer(properties);
           elements.add(map);
         }
       }
     }
 
     return new jsAst.ArrayInitializer(elements);
   }
 }