Use failedAt in more places

pkg/compiler/lib/src/kernel/native_basic_data.dart

 // Copyright (c) 2017, 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.
 
 // TODO(johnniwinther): Make this a separate library.
 part of dart2js.kernel.element_map;
 
 class KernelAnnotationProcessor implements AnnotationProcessor {
   final KernelToElementMapForImpactImpl elementMap;
   final NativeBasicDataBuilder _nativeBasicDataBuilder;
 
   KernelAnnotationProcessor(this.elementMap, this._nativeBasicDataBuilder);
 
   void extractNativeAnnotations(LibraryEntity library) {
     ElementEnvironment elementEnvironment = elementMap.elementEnvironment;
     CommonElements commonElements = elementMap.commonElements;
 
     elementEnvironment.forEachClass(library, (ClassEntity cls) {
       String annotationName;
       // TODO(johnniwinther): Make [_getClassMetadata] public and at test to
       // guard against misuse.
       for (ConstantValue value in elementMap._getClassMetadata(cls)) {
         String name = readAnnotationName(
             cls, value, commonElements.nativeAnnotationClass);
         if (annotationName == null) {
           annotationName = name;
         } else if (name != null) {
-          throw new SpannableAssertionFailure(
-              cls, 'Too many name annotations.');
+          failedAt(cls, 'Too many name annotations.');
         }
       }
       if (annotationName != null) {
         _nativeBasicDataBuilder.setNativeClassTagInfo(cls, annotationName);
       }
     });
   }
 
   void extractJsInteropAnnotations(LibraryEntity library) {
     // TODO(redemption): Implement this.
   }
 
   @override
   void processJsInteropAnnotations(
       NativeBasicData nativeData, NativeDataBuilder nativeDataBuilder) {
     // TODO(redemption): Implement this.
   }
 }