Add missing using statements for JNI types.

chrome/browser/android/warmup_manager.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/warmup_manager.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_android.h"
 #include "jni/WarmupManager_jni.h"
 #include "url/gurl.h"
 
+using base::android::JavaParamRef;
+
 static void PreconnectUrlAndSubresources(JNIEnv* env,
                                          const JavaParamRef<jclass>& clazz,
                                          const JavaParamRef<jobject>& jprofile,
                                          const JavaParamRef<jstring>& url_str) {
   if (url_str) {
     GURL url = GURL(base::android::ConvertJavaStringToUTF8(env, url_str));
     Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
     if (profile) {
       profile->GetNetworkPredictor()->PreconnectUrlAndSubresources(url, GURL());
     }
   }
 }
 
 
 // Register native methods.
 bool RegisterWarmupManager(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }