Change codec interfaces to expect const uint8_t* for input data

Change-Id: Ib2d92a38a32e296ae8280dfbe7be63523e4795c0
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/3947
Reviewed-by: Henry Robinson <henry@cloudera.com>
Tested-by: jenkins
(cherry picked from commit 81d45223ba32b311db50bdfee25bb2ea27219839)
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/3959