Add missing using statements for JNI types.

chrome/browser/android/sessions/session_tab_helper_android.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/android/sessions/session_tab_helper_android.h"
 
 #include "base/android/jni_android.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "content/public/browser/web_contents.h"
 #include "jni/SessionTabHelper_jni.h"
 
+using base::android::JavaParamRef;
+
 // static
 jint IdForTab(JNIEnv* env,
               const JavaParamRef<jclass>& clazz,
               const JavaParamRef<jobject>& java_web_contents) {
   content::WebContents* web_contents =
       content::WebContents::FromJavaWebContents(java_web_contents);
   CHECK(web_contents);
   return SessionTabHelper::IdForTab(web_contents);
 }
 
 bool RegisterSessionTabHelper(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }