jni_generator: Pass object parameters as JavaParamRef.

chrome/browser/android/metrics/variations_session.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 "chrome/browser/android/metrics/variations_session.h"
 
 #include "base/android/jni_string.h"
 #include "chrome/browser/browser_process.h"
 #include "components/variations/service/variations_service.h"
 #include "jni/VariationsSession_jni.h"
 
 namespace {
 
 // Tracks whether VariationsService::OnAppEnterForeground() has been called
 // previously, in order to set the restrict mode param before the first call.
 bool g_on_app_enter_foreground_called = false;
 
 }  // namespace
 
-static void StartVariationsSession(JNIEnv* env,
-                                   jobject obj,
-                                   jstring jrestrict_mode) {
+static void StartVariationsSession(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jstring>& jrestrict_mode) {
   DCHECK(g_browser_process);
 
   chrome_variations::VariationsService* variations_service =
       g_browser_process->variations_service();
   // Triggers an OnAppEnterForeground on the VariationsService. This may fetch
   // a new seed.
   if (variations_service) {
     std::string restrict_mode =
         base::android::ConvertJavaStringToUTF8(env, jrestrict_mode);
     if (!restrict_mode.empty() && !g_on_app_enter_foreground_called)
       variations_service->SetRestrictMode(restrict_mode);
     variations_service->OnAppEnterForeground();
     g_on_app_enter_foreground_called = true;
   }
 }
 
 namespace chrome {
 namespace android {
 
 // Register native methods
 bool RegisterVariationsSession(JNIEnv* env) { return RegisterNativesImpl(env); }
 
 }  // namespace android
 }  // namespace chrome