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/mediadrm/include/WVDrmPlugin.h

@@ -32,7 +32,6 @@ using android::status_t;
 using android::String8;
 using android::Vector;
 using std::map;
-using wvcdm::CdmEventType;
 using wvcdm::CdmSessionId;
 using wvcdm::CdmResponseType;
 using wvcdm::WvContentDecryptionModule;
@@ -140,8 +139,9 @@ class WVDrmPlugin : public android::DrmPlugin,
                            const Vector<uint8_t>& wrappedKey,
                            Vector<uint8_t>& signature);
 
-  virtual void OnEvent(const CdmSessionId& cdmSessionId,
-                       CdmEventType cdmEventType);
+  virtual void OnSessionRenewalNeeded(const CdmSessionId& cdmSessionId);
+
+  virtual void OnSessionExpiration(const CdmSessionId& cdmSessionId);
 
  private:
   DISALLOW_EVIL_CONSTRUCTORS(WVDrmPlugin);