Currently the CDM requires the caller to specify init data both on key generation and renewal requests. With this change the CDM relaxes this requirement for renewals. Bug: 8732893 Merge of https://widevine-internal-review.googlesource.com/#/c/5322/ from Widevine CDM repo Change-Id: Idf4ad2bdb20023da4f30bc369ed87eb811c1c4d9