anchor.diff:  
       var sourceFactory = new SourceFactory(<UriResolver>[
         new DartUriResolver(sdk),
  -      new InSummaryUriResolver(resourceProvider, summaryDataStore),
  +      new TrackingInSummaryUriResolver(
  +          new InSummaryUriResolver(resourceProvider, summaryDataStore),
  +          dependencyTracker),
         new ExplicitSourceResolver(uriToFileMap)
       ]);
   
  
positive.code:     return cache.get(inputs, path);
    }
  }
  
negative.code:         }
        }
  
        ErrorSeverity severity;
        if (options.buildSummaryOnly) {
          severity = ErrorSeverity.NONE;
        } else {
          // Process errors.
          await _printErrors(outputPath: options.buildAnalysisOutput);
          severity = await _computeMaxSeverity();
        }
  
        if (dependencyTracker != null) {
          io.File file = new io.File(dependencyTracker.outputPath);
          file.writeAsStringSync(dependencyTracker.dependencies.join('\n'));
        }
  
        return severity;
      });
    }
  
  