constructor(dependencies, errors, source) {
    /** @const */
    this.dependencies = dependencies;
    /** @const */
    this.errors = errors;
    /** @const */
    this.source = source;
    /** @const */
    this.isFromDepsFile = source === ParseResult.Source.GOOG_ADD_DEPENDENCY;
    /** @const {boolean} */
    this.hasFatalError = errors.some(e => e.fatal);
  }
@param {!Array<!depGraph.Dependency>} dependencies
@param {!Array<!ParseError>} errors
@param {!ParseResult.Source} source