code: def CheckHeaderFileIncluded(filename, include_state, error):
    
  
    # Do not check test files
    if filename.endswith('_test.cc') or filename.endswith('_unittest.cc'):
      return
  
    fileinfo = FileInfo(filename)
    headerfile = filename[0:len(filename) - 2] + 'h'
    if not os.path.exists(headerfile):
      return
    headername = FileInfo(headerfile).RepositoryName()
    first_include = 0
    for section_list in include_state.include_list:
      for f in section_list:
        if headername in f[0] or f[0] in headername:
          return
        if not first_include:
          first_include = f[1]
  
    error(filename, first_include, 'build/include', 5,
          '%s should include its header file %s' % (fileinfo.RepositoryName(),
                                                    headername))
docs: Logs an error if a .cc file does not include its header.