jni_generator: Make all object-returning natives return ScopedJavaLocalRef.

chrome/browser/ui/android/javascript_app_modal_dialog_android.cc

 // Copyright (c) 2012 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/ui/android/javascript_app_modal_dialog_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "chrome/browser/ui/app_modal/chrome_javascript_native_dialog_factory.h"
 #include "components/app_modal/app_modal_dialog_queue.h"
@@ skipping 118 matching lines @@
   dialog_->OnCancel(should_suppress_js_dialogs);
   delete this;
 }
 
 const ScopedJavaGlobalRef<jobject>&
     JavascriptAppModalDialogAndroid::GetDialogObject() const {
   return dialog_jobject_;
 }
 
 // static
-jobject GetCurrentModalDialog(JNIEnv* env, jclass clazz) {
+ScopedJavaLocalRef<jobject> GetCurrentModalDialog(JNIEnv* env, jclass clazz) {
   app_modal::AppModalDialog* dialog =
       app_modal::AppModalDialogQueue::GetInstance()->active_dialog();
   if (!dialog || !dialog->native_dialog())
-    return NULL;
+    return ScopedJavaLocalRef<jobject>();
 
   JavascriptAppModalDialogAndroid* js_dialog =
       static_cast<JavascriptAppModalDialogAndroid*>(dialog->native_dialog());
-  return js_dialog->GetDialogObject().obj();
+  return ScopedJavaLocalRef<jobject>(js_dialog->GetDialogObject());
 }
 
 // static
 bool JavascriptAppModalDialogAndroid::RegisterJavascriptAppModalDialog(
     JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 JavascriptAppModalDialogAndroid::~JavascriptAppModalDialogAndroid() {
   // In case the dialog is still displaying, tell it to close itself.
@@ skipping 27 matching lines @@
 };
 
 }  // namespace
 
 void InstallChromeJavaScriptNativeDialogFactory() {
   app_modal::JavaScriptDialogManager::GetInstance()->
       SetNativeDialogFactory(
           make_scoped_ptr(new ChromeJavaScriptNativeDialogAndroidFactory));
 }