message: Format with predefined_style when a style cannot be obtained
diff: @@ -44,7 +44,7 @@ std::vector<tooling::Replacement> ClangFormatDocument(
  }
  auto format_result = reformat(
  - *style, working_file->buffer_content,
  + style ? *style : predefined_style, working_file->buffer_content,
  llvm::ArrayRef<tooling::Range>(tooling::Range(start, end - start)),
  working_file->filename);
  return std::vector<tooling::Replacement>(format_result.begin(),
  