code: def add_debugged_source_file(self, debugged_source_file):
      
      # TODO(cais): Should the key include a host name, for certain distributed
      #   cases?
      key = debugged_source_file.file_path
      self._source_file_host[key] = debugged_source_file.host
      self._source_file_last_modified[key] = debugged_source_file.last_modified
      self._source_file_bytes[key] = debugged_source_file.bytes
      self._source_file_content[key] = debugged_source_file.lines
docs: Add a DebuggedSourceFile proto.