Add missing using statements for JNI types.

components/sync/android/model_type_helper.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 "components/sync/android/model_type_helper.h"
 
 #include <string>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "components/sync/base/model_type.h"
 #include "jni/ModelTypeHelper_jni.h"
 
+using base::android::JavaParamRef;
+using base::android::ScopedJavaLocalRef;
+
 namespace syncer {
 
 static ScopedJavaLocalRef<jstring> ModelTypeToNotificationType(
     JNIEnv* env,
     const JavaParamRef<jclass>& clazz,
     jint model_type_int) {
   std::string model_type_string;
   ModelType model_type = static_cast<ModelType>(model_type_int);
   if (!RealModelTypeToNotificationType(model_type, &model_type_string)) {
     NOTREACHED() << "No string representation of model type " << model_type;
   }
   return base::android::ConvertUTF8ToJavaString(env, model_type_string);
 }
 
 bool RegisterModelTypeHelperJni(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace syncer