[Chromecast] Make EME persistent license support optional

chromecast/renderer/key_systems_cast.h

Index: chromecast/renderer/key_systems_cast.h
diff --git a/chromecast/renderer/key_systems_cast.h b/chromecast/renderer/key_systems_cast.h
index 351abef30f2a9ae3152528dacd80a7bc6b80a0e2..805138f3ee1115813a8c86203e53d4d60804dd2b 100644
--- a/chromecast/renderer/key_systems_cast.h
+++ b/chromecast/renderer/key_systems_cast.h
@@ -17,7 +17,8 @@ namespace shell {
 
 void AddChromecastKeySystems(
     std::vector<std::unique_ptr<::media::KeySystemProperties>>*
-        key_systems_properties);
+        key_systems_properties,
+    bool enable_persistent_license_support);
 
 }  // namespace shell
 }  // namespace chromecast