[ Merge of http://go/wvgerrit/96514 ]
The combined decryption call feature was introduced in android R.
In earlier releases, subsamples were passed one at a time for
decryption within the plugin. A decryption request that consists
entirely of clear data should be passed on to OEMCrypto even if
no keys are loaded.
A sample might consist of subsamples of clear and protected data.
In legacy mode, this proved to be an issue for OEMCrypto if the clear
subsamples were passed on but the protected ones were rejected (b/110251447).
For legacy mode and in the absence of keys being loaded, the subsample will
be passed to OEMCrypto only if the clear lead/frame is in a single subsample
and not broken up across multiple subsamples.
Bug: 150316417
Test: WV android unit/integration tests
Change-Id: Iff8ae8f58530cb9c5d31ce388742443ae807c16f
734aea940b