jni_generator: Pass object parameters as JavaParamRef.

ui/android/window_android.cc

 // Copyright 2013 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 "ui/android/window_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/jni_weak_ref.h"
@@ skipping 118 matching lines @@
   return Java_WindowAndroid_canRequestPermission(
       env,
       GetJavaObject().obj(),
       base::android::ConvertUTF8ToJavaString(env, permission).obj());
 }
 
 // ----------------------------------------------------------------------------
 // Native JNI methods
 // ----------------------------------------------------------------------------
 
-jlong Init(JNIEnv* env, jobject obj) {
+jlong Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   WindowAndroid* window = new WindowAndroid(env, obj);
   return reinterpret_cast<intptr_t>(window);
 }
 
 }  // namespace ui