anchor.diff:        _component.libraries.remove(library);
         _component.root.removeChild('${library.importUri}');
         _component.uriToSource.remove(libraryUri);
  +      _dillTarget.loader.builders.remove(library.importUri);
  +      _dillTarget.loader.libraries.remove(library);
  +      _dillTarget.loader.uriToSource.remove(libraryUri);
         _results.remove(library.importUri);
   
         // Recursively invalidate dependencies.
  
positive.code:     }
  
      return _runWithFrontEndContext('Compile', () async {
        // TODO(brianwilkerson) Determine whether this await is necessary.
        await null;
        try {
          var dillTarget =
              new DillTarget(_options.ticker, uriTranslator, _options.target);
  
          // Append all libraries what we still have in the current component.
          await _logger.runAsync('Load dill libraries', () async {
            // TODO(brianwilkerson) Determine whether this await is necessary.
            await null;
            dillTarget.loader.appendLibraries(_component);
            await dillTarget.buildOutlines();
          });
  
          // Create the target to compile the library.
          var kernelTarget = new _AnalyzerKernelTarget(_fileSystem, dillTarget,
              uriTranslator, new AnalyzerMetadataCollector());
          kernelTarget.read(uri);
  
  
negative.code:   }
  
    Future<T> _runWithFrontEndContext<T>(String msg, Future<T> f()) async {
      return await CompilerContext.runWithOptions(_options, (context) {
        context.disableColors();
        return _logger.runAsync(msg, f);
  