Support renew on load

[ Merge of http://go/wvgerrit/164477 ]

Renew on load is supported when OEMCrypto is >= v18.
A new class, policy_timer_v18 has been added to support this
functionality. In addtition,offsets of renewal from first decrypt
and license start are also included.

Bug: 256038127
Test: GtsMediaTestCases
Change-Id: Ib18af3096d1d8807af6a03fd2f84783123ab6b6d

libwvdrmengine/cdm/core/include/policy_timers_v18.h

@@ -0,0 +1,56 @@
+// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+
+#ifndef WVCDM_CORE_POLICY_TIMERS_V18_H_
+#define WVCDM_CORE_POLICY_TIMERS_V18_H_
+
+#include "disallow_copy_and_assign.h"
+#include "license_protocol.pb.h"
+#include "policy_timers.h"
+#include "wv_cdm_types.h"
+
+namespace wvcdm {
+
+// OEMCrypto v18 includes support for renewing licenses on load by using
+// |initial_renewal_delay_base| and TimerDelayBase.
+//
+// Backward compatibility may be needed if
+//  * OEMCrypto has not been upgraded to v18
+//  * Licenses were persisted before the device was upgraded to v18
+
+class PolicyTimersV18 : public PolicyTimers {
+ public:
+  PolicyTimersV18() {}
+
+  ~PolicyTimersV18() override {}
+
+  // UpdateLicense is used in handling a license response, a renewal response,
+  // or when restoring or releasing a persistent license.
+  // In a renewal the response may only contain policy fields that have
+  // changed. In this case an exact copy is not what we want to happen.
+  // |renewal_start_time_| is set to the time mentioned in the renewal
+  // response.
+  // UpdateLicense will return false if |license_start_time| is not
+  // present or playback is not allowed due to policy or timer duration
+  // expiration.
+  bool UpdateLicense(int64_t current_time,
+                     const video_widevine::License& license) override;
+
+  // Call this on first decrypt to set the start of playback.
+  void BeginDecryption(int64_t current_time) override;
+
+  // Renewal related methods
+  bool HasRenewalDelayExpired(int64_t current_time) override;
+
+ private:
+  // Indicates whether this is an initial license or a renewal
+  bool license_renewal_ = false;
+  bool renew_on_first_decrypt_ = false;
+
+  CORE_DISALLOW_COPY_AND_ASSIGN(PolicyTimersV18);
+};
+
+}  // namespace wvcdm
+
+#endif  // WVCDM_CORE_POLICY_TIMERS_V18_H_