Add missing using statements for JNI types.

chrome/browser/ui/android/tab_model/single_tab_model.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/ui/android/tab_model/single_tab_model.h"
 
 #include "base/android/jni_android.h"
 #include "chrome/browser/android/tab_android.h"
 #include "chrome/browser/android/webapps/single_tab_mode_tab_helper.h"
 #include "content/public/browser/web_contents.h"
 #include "jni/SingleTabModel_jni.h"
 
+using base::android::JavaParamRef;
+
 static void PermanentlyBlockAllNewWindows(
     JNIEnv* env,
     const JavaParamRef<jclass>& clazz,
     const JavaParamRef<jobject>& j_tab_android) {
   TabAndroid* tab = TabAndroid::GetNativeTab(env, j_tab_android);
   if (!tab)
     return;
 
   content::WebContents* web_contents = tab->web_contents();
   if (!web_contents)
     return;
 
   SingleTabModeTabHelper* tab_helper =
       SingleTabModeTabHelper::FromWebContents(web_contents);
   tab_helper->PermanentlyBlockAllNewWindows();
 }
 
 // Register native methods
 bool RegisterSingleTabModel(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }