anchor.diff:  import 'package:analyzer/src/context/context.dart';
   import 'package:analyzer/src/dart/analysis/driver.dart';
   import 'package:analyzer/src/dart/analysis/file_state.dart';
  +import 'package:analyzer/src/dart/element/element.dart';
  +import 'package:analyzer/src/dart/element/handle.dart';
   import 'package:analyzer/src/generated/engine.dart'
       show AnalysisContext, AnalysisEngine, AnalysisOptions;
   import 'package:analyzer/src/generated/source.dart';
  
positive.code:         byteStore.put(key, bytes);
        });
  
        AnalysisContextImpl analysisContext = _createAnalysisContext(
            options, declaredVariables, sourceFactory, store);
        analysisContext.contentCache = new _ContentCacheWrapper(fsState);
  
        return new LibraryContext._(store, analysisContext);
      });
    }
  
    LibraryContext._(this.store, this._analysisContext);
  
    /**
     * Computes a [CompilationUnitElement] for the given library/unit pair.
     */
    CompilationUnitElement computeUnitElement(
        Source librarySource, Source unitSource) {
      return _analysisContext.computeResult(
          new LibrarySpecificUnit(librarySource, unitSource),
          COMPILATION_UNIT_ELEMENT);
    }
  
    /**
  
negative.code: import 'package:analyzer/src/summary/idl.dart';
  import 'package:analyzer/src/summary/link.dart';
  import 'package:analyzer/src/summary/package_bundle_reader.dart';
  import 'package:front_end/src/base/performace_logger.dart';
  import 'package:front_end/src/byte_store/byte_store.dart';
  
  