Assert that we don't mix K and J elements

pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart

 // Copyright (c) 2016, 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.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../compiler.dart';
 import '../constants/expressions.dart';
@@ skipping 45 matching lines @@
   /// Sometimes for resolution the resolved AST element needs to change (for
   /// example, if we're inlining, or if we're in a constructor, but then also
   /// constructing the field values). We keep track of this with a stack.
   final List<ResolvedAst> _resolvedAstStack = <ResolvedAst>[];
 
   final native.BehaviorBuilder nativeBehaviorBuilder;
 
   KernelAstAdapter(this.kernel, this._backend, this._resolvedAst,
       this._nodeToAst, this._nodeToElement)
       : nativeBehaviorBuilder = new native.ResolverBehaviorBuilder(
-            _backend.compiler, _backend.nativeBasicData) {
+            _backend.compiler, _backend.frontendStrategy.nativeBasicData) {
     KernelJumpTarget.index = 0;
     // TODO(het): Maybe just use all of the kernel maps directly?
     for (FieldElement fieldElement in kernel.fields.keys) {
       _nodeToElement[kernel.fields[fieldElement]] = fieldElement;
     }
     for (FunctionElement functionElement in kernel.functions.keys) {
       _nodeToElement[kernel.functions[functionElement]] = functionElement;
     }
     for (ClassElement classElement in kernel.classes.keys) {
       _nodeToElement[kernel.classes[classElement]] = classElement;
@@ skipping 603 matching lines @@
   TypeMask selectorTypeOf(Selector selector, TypeMask mask) {
     return TypeMaskFactory.inferredTypeForSelector(
         selector, mask, _globalInferenceResults);
   }
 
   TypeMask typeFromNativeBehavior(
       native.NativeBehavior nativeBehavior, ClosedWorld closedWorld) {
     return TypeMaskFactory.fromNativeBehavior(nativeBehavior, closedWorld);
   }
 }