anchor.diff:  import 'package:analyzer/src/generated/sdk.dart';
   import 'package:analyzer/src/generated/source.dart';
   import 'package:analyzer/src/summary/idl.dart' show PackageBundle;
  +import 'package:analyzer/src/summary/summary_file_builder.dart';
   
   class MockSdk implements DartSdk {
     static const MockSdkLibrary LIB_CORE = const MockSdkLibrary(
  
positive.code:    * The [AnalysisContext] which is used for all of the sources.
     */
    InternalAnalysisContext _analysisContext;
  
    MockSdk({resource.ResourceProvider resourceProvider})
        : provider = resourceProvider ?? new resource.MemoryResourceProvider() {
  
negative.code:   }
  
    @override
    PackageBundle getLinkedBundle() {
      if (_bundle == null) {
        List<Source> librarySources = sdkLibraries
            .map((SdkLibrary library) => mapDartUri(library.shortName))
            .toList();
        List<int> bytes = new SummaryBuilder(
                librarySources, context, context.analysisOptions.strongMode)
            .build();
        _bundle = new PackageBundle.fromBuffer(bytes);
      }
      return _bundle;
    }
  
    @override
    SdkLibrary getSdkLibrary(String dartUri) {
  