merge of http://go/wvgerrit/14807 from the widevine repo.
The mediaDrm API only allows for a single provisioning attempt at a time.
If concurrent provisioning attempts occur, resources are released from
all but the last request, in order to allow at least that one to be successful.
Any provisioning responses received before one from the last request will
be rejected. A side-effect was that all provisioning resources would
then be released. This caused a provisioning response from the last attempt
to be rejected as well. This CL corrects this behavior and releases resources
only if a provisioning attempt is successful.
The side-effect is that, if the response to the last request is not received
or failure occurs while processing, a crypto session may be held until the
next provisioning attempt.
In other cases of concurrency, provisioning responses to requests other than
the last which are received after the last response will be declared successful.
b/21879484
Change-Id: I3a840ceda1a16ee6adb40c2dbca6c4adf3da12c3
a1895e7e2e