jni_generator: Pass object parameters as JavaParamRef.

chromecast/base/chromecast_config_android.cc

Index: chromecast/base/chromecast_config_android.cc
diff --git a/chromecast/base/chromecast_config_android.cc b/chromecast/base/chromecast_config_android.cc
index f16b4733069fa4b63d05f6b61dc5ac820beba58a..168faa25991111f31cc610e92edb48833bb2c921 100644
--- a/chromecast/base/chromecast_config_android.cc
+++ b/chromecast/base/chromecast_config_android.cc
@@ -47,7 +47,9 @@ void ChromecastConfigAndroid::SetSendUsageStatsChangedCallback(
 }
 
 // Called from Java.
-void SetSendUsageStatsEnabled(JNIEnv* env, jclass caller, jboolean enabled) {
+void SetSendUsageStatsEnabled(JNIEnv* env,
+                              const JavaParamRef<jclass>& caller,
+                              jboolean enabled) {
   ChromecastConfigAndroid::GetInstance()->
       send_usage_stats_changed_callback().Run(enabled);
 }