The CDM session was being destroyed before the policy timer was stopped and before the session was removed from a list of active sessions. This allowed race conditions, where the policy timer would try to evaluate policy for a closed session. This led to segfaults. b/11338324 Merge of https://widevine-internal-review.googlesource.com/#/c/8240/1 from the widevine cdm repo. Change-Id: Ib159ccfdb763a47da573f5c06c0793c2c63886c4