anchor.diff:     * resolved in some contexts.
      */
     ResolverProvider fileResolverProvider;
  +
  +  /**
  +   * The package resolver provider used to override the way package URI's are
  +   * resolved in some contexts.
  +   */
  +  ResolverProvider packageResolverProvider;
   
     /**
      * The manager of pub package summaries.
  
positive.code:         analysisServer.sdkManager, analysisServer.overlayState);
      builder.defaultOptions = options;
      builder.fileResolverProvider = analysisServer.fileResolverProvider;
      builder.defaultPackageFilePath = defaultPackageFilePath;
      builder.defaultPackagesDirectoryPath = defaultPackagesDirectoryPath;
      return builder;
  
negative.code:           defaultContextOptions);
      }
      this.fileResolverProvider = fileResolverProvider;
      this.packageResolverProvider = packageResolverProvider;
      ServerContextManagerCallbacks contextManagerCallbacks =
          new ServerContextManagerCallbacks(this, resourceProvider);
      contextManager.callbacks = contextManagerCallbacks;
  