Plugin to provide getPropertyByteArray("deviceSignedCsrPayload")
which returns the signed CSR payload for device registration. It
queries both BCC and device info to be set in plugin before calling this
getPropertyByteArray("deviceSignedCsrPayload") method. The returned csr
payload will be used by assemble the device CSR by the caller for device
registration.
Bug: 286556950
Test: build WV DRM plugin
Merged from https://widevine-internal-review.googlesource.com/178891
Merged from https://widevine-internal-review.googlesource.com/179731
Change-Id: I65d89ed998dd292fc656af2f91f4472c1b5ec33c