Replace generic OnEvent with actual event callbacks

Also pass session_id and event_listener to PolicyEngine to make it easier
to dispatch events from PolicyEngine.

Bug: 19771437

Merged from Widevine CDM repo:
https://widevine-internal-review.googlesource.com/#/c/13816/

Change-Id: I5723cb371cb3c43c945051af3402b09069ba5859

libwvdrmengine/cdm/core/include/policy_engine.h

@@ -16,12 +16,14 @@ using video_widevine_server::sdk::LicenseIdentification;
 
 class Clock;
 class CryptoSession;
+class WvCdmEventListener;
 
 // This acts as an oracle that basically says "Yes(true) you may still decrypt
 // or no(false) you may not decrypt this data anymore."
 class PolicyEngine {
  public:
-  explicit PolicyEngine(CryptoSession* crypto_session);
+  PolicyEngine(CdmSessionId session_id, WvCdmEventListener* event_listener,
+               CryptoSession* crypto_session);
   virtual ~PolicyEngine();
 
   // The value returned should be taken as a hint rather than an absolute
@@ -32,11 +34,9 @@ class PolicyEngine {
   virtual bool CanDecrypt(const KeyId& key_id);
 
   // OnTimerEvent is called when a timer fires. It notifies the Policy Engine
-  // that the timer has fired and that it should check whether any events have
-  // occurred since the last timer event. If so, it sets event_occurred to true
-  // and sets event to point to the event that occurred. If not, it sets
-  // event_occurred to false.
-  virtual void OnTimerEvent(bool* event_occurred, CdmEventType* event);
+  // that the timer has fired and dispatches the relevant events through
+  // |event_listener_|.
+  virtual void OnTimerEvent();
 
   // SetLicense is used in handling the initial license response. It stores
   // an exact copy of the policy information stored in the license.
@@ -126,6 +126,10 @@ class PolicyEngine {
   int64_t next_renewal_time_;
   int64_t policy_max_duration_seconds_;
 
+  // Used to dispatch CDM events.
+  CdmSessionId session_id_;
+  WvCdmEventListener* event_listener_;
+
   MaxResEngine max_res_engine_;
   scoped_ptr<Clock> clock_;