(This is a merge of http://go/wvgerrit/46203)
Previously, IsProvisioned() only confirmed the existence of a
certificate file, not whether the contents of that file were actually
valid. This patch changes its behavior so that it actually validates the
loadability of the file before returning.
This is sufficient to resolve Netflix's use case in b/65835227, but it
is only part of the solution for Android's use case in b/72353451. A
second patch will be required to cover cases where the certificate can
be loaded but cannot be used with the current OEMCrypto or with the
server.
Bug: 65835227
Bug: 72353451
Test: Android and CE CDM unit tests
Change-Id: Id3987a6f3c4097d7d356dfa631b023287354439a
db0911df54