Add a TODO comment to describe when we can remove the const_cast for

the NSS function SGN_Update.

R=rafaelw
BUG=20669
TEST=none
Review URL: http://codereview.chromium.org/218035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27163 0039d316-1c4b-4281-b951-d872f2087c98

base/crypto/signature_creator_nss.cc

@@ -47,6 +47,8 @@ SignatureCreator::~SignatureCreator() {
 }
 
 bool SignatureCreator::Update(const uint8* data_part, int data_part_len) {
+  // TODO(wtc): Remove this const_cast when we require NSS 3.12.5.
+  // See NSS bug https://bugzilla.mozilla.org/show_bug.cgi?id=518255
   SECStatus rv = SGN_Update(sign_context_,
                             const_cast<unsigned char*>(data_part),
                             data_part_len);