jni_generator: Pass object parameters as JavaParamRef.

mandoline/app/android/mandoline_activity.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/android/jni_string.h"
 #include "jni/MandolineActivity_jni.h"
 #include "mandoline/ui/desktop_ui/public/interfaces/launch_handler.mojom.h"
 #include "mojo/runner/android/main.h"
 #include "mojo/runner/context.h"
 
 namespace mandoline {
 
-static void LaunchURL(JNIEnv* env, jclass clazz, jstring jurl) {
+static void LaunchURL(JNIEnv* env,
+                      const JavaParamRef<jclass>& clazz,
+                      const JavaParamRef<jstring>& jurl) {
   LaunchHandlerPtr launch_handler;
   mojo::runner::GetContext()->application_manager()->ConnectToService(
       GURL("mojo:phone_ui"), &launch_handler);
   launch_handler->LaunchURL(
       base::android::ConvertJavaStringToUTF8(env, jurl));
 }
 
 bool RegisterMandolineActivity(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace mandoline