net: retain leading zero bytes in X.509 serial numbers.

net/base/x509_certificate.h

Index: net/base/x509_certificate.h
diff --git a/net/base/x509_certificate.h b/net/base/x509_certificate.h
index b4677d23744bddafe510971dc2a81e9e1bdf525a..057e6aaccad50228d43a7e72ab52ea66dea94a9d 100644
--- a/net/base/x509_certificate.h
+++ b/net/base/x509_certificate.h
@@ -424,12 +424,7 @@ class NET_EXPORT X509Certificate
                      CRLSet* crl_set,
                      CertVerifyResult* verify_result) const;
 
-  // The serial number, DER encoded.
-  // NOTE: keep this method private, used by IsBlacklisted only.  To simplify
-  // IsBlacklisted, we strip the leading 0 byte of a serial number, used to
-  // encode a positive DER INTEGER (a signed type) with a most significant bit
-  // of 1.  Other code must not use this method for general purpose until this
-  // is fixed.
+  // The serial number, DER encoded, possibly including a leading 00 byte.
   const std::string& serial_number() const { return serial_number_; }
 
   // IsBlacklisted returns true if this certificate is explicitly blacklisted.