code: void appendGoogRequiresTo(StringBuilder sb) {
      for (GoogRequire require : googRequires.values()) {
        // TODO(lukes): we need some namespace management here... though really we need namespace
        // management with all declarations... The problem is that a require could introduce a name
        // alias that conflicts with a symbol defined elsewhere in the file.
        require.writeTo(sb);
      }
    }
docs: Should only be used by {@link GenJsCodeVisitor#visitSoyFileNode}.