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Pad key value when crypto_mode is DVB_CSA, so that the key length is always 16 bytes.
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Minor comment and example code update.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219860612
(2) Add a new enum value for kDvbCsa.
(3) Allow caller to specify CTR, CBC, as well as CSA when using the ecm genertor from the SDK.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219707788
Following example: []/video/widevine/export/provisioning_sdk/public/provisioning_status.h
and
[]/video/widevine/export/exported_root/util/status.h
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=218918745