jni_generator: Make all object-returning natives return ScopedJavaLocalRef.

base/android/jni_generator/sample_for_tests.cc

Index: base/android/jni_generator/sample_for_tests.cc
diff --git a/base/android/jni_generator/sample_for_tests.cc b/base/android/jni_generator/sample_for_tests.cc
index 61dd7f38eb2cf1c70ff83a34bee3ff5f6e67a498..a05909a46e66ab4976092a99a0018a070b16ab0c 100644
--- a/base/android/jni_generator/sample_for_tests.cc
+++ b/base/android/jni_generator/sample_for_tests.cc
@@ -81,8 +81,8 @@ static jfloat GetFloatFunction(JNIEnv*, jclass) {
 static void SetNonPODDatatype(JNIEnv*, jobject, jobject) {
 }
 
-static jobject GetNonPODDatatype(JNIEnv*, jobject) {
-  return NULL;
+static ScopedJavaLocalRef<jobject> GetNonPODDatatype(JNIEnv*, jobject) {
+  return ScopedJavaLocalRef<jobject>();
 }
 
 static jint InnerFunction(JNIEnv*, jclass) {