PVS-Studio warning V547 for Chromium

static void CharAdvance(char** buffer,
                        size_t* buffer_size,
                        size_t count) {
  if (count < 0) {
    NaClFatal("Unable to advance buffer by count!");
  } else {
  ...
}

This suspicious code was found in Chromium project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression 'count < 0' is always false. Unsigned type value is never < 0.  ncdecode_tablegen  ncdecode_tablegen.c  197

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