jni_generator: Make all object-returning natives return ScopedJavaLocalRef.

chrome/browser/android/omnibox/autocomplete_controller_android.cc

 // Copyright 2014 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/omnibox/autocomplete_controller_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string16.h"
@@ skipping 503 matching lines @@
 static jlong Init(JNIEnv* env, jobject obj, jobject jprofile) {
   Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
   if (!profile)
     return 0;
 
   AutocompleteControllerAndroid* native_bridge =
       AutocompleteControllerAndroid::Factory::GetForProfile(profile, env, obj);
   return reinterpret_cast<intptr_t>(native_bridge);
 }
 
-static jstring QualifyPartialURLQuery(
-    JNIEnv* env, jclass clazz, jstring jquery) {
+static ScopedJavaLocalRef<jstring> QualifyPartialURLQuery(JNIEnv* env,
+                                                          jclass clazz,
+                                                          jstring jquery) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   if (!profile)
-    return NULL;
+    return ScopedJavaLocalRef<jstring>();
   AutocompleteMatch match;
   base::string16 query_string(ConvertJavaStringToUTF16(env, jquery));
   AutocompleteClassifierFactory::GetForProfile(profile)->Classify(
       query_string,
       false,
       false,
       OmniboxEventProto::INVALID_SPEC,
       &match,
       NULL);
   if (!match.destination_url.is_valid())
-    return NULL;
+    return ScopedJavaLocalRef<jstring>();
 
   // Only return a URL if the match is a URL type.
   if (match.type != AutocompleteMatchType::URL_WHAT_YOU_TYPED &&
       match.type != AutocompleteMatchType::HISTORY_URL &&
       match.type != AutocompleteMatchType::NAVSUGGEST)
-    return NULL;
+    return ScopedJavaLocalRef<jstring>();
 
   // As we are returning to Java, it is fine to call Release().
-  return ConvertUTF8ToJavaString(env, match.destination_url.spec()).Release();
+  return ConvertUTF8ToJavaString(env, match.destination_url.spec());
 }
 
 static void PrefetchZeroSuggestResults(JNIEnv* env, jclass clazz) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   if (!profile)
     return;
 
   if (!OmniboxFieldTrial::InZeroSuggestPersonalizedFieldTrial())
     return;
 
   // ZeroSuggestPrefetcher deletes itself after it's done prefetching.
   new ZeroSuggestPrefetcher(profile);
 }
 
 // Register native methods
 bool RegisterAutocompleteControllerAndroid(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }