Cas Client repo update-2.

-Parse EMM in Cas plugin
-Entitlement key rotation support
-Multi_content_license support

plugin/include/widevine_cas_session_map.h

@@ -34,6 +34,8 @@ class WidevineCasSessionMap {
   CasSessionPtr GetSession(WvCasSessionId cas_session_id) const;
   // Remove an entry in the map.
   void RemoveSession(WvCasSessionId cas_session_id);
+  // Retrieves all the session ids.
+  std::vector<CasSessionPtr> GetAllSessions() const;
 
   // Returns a reference to the map.
   static WidevineCasSessionMap& instance();