Expose API to detect when captive portal probe was blocked on Android

net/android/unittest_support/AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!--
 Copyright 2014 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.
 -->
 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="org.chromium.native_test"
       android:versionCode="1"
       android:versionName="1.0">
 
     <uses-sdk android:minSdkVersion="16" android:targetSdkVersion="23" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS"/>
     <uses-permission android:name="android.permission.BLUETOOTH"/>
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
     <uses-permission android:name="android.permission.CAMERA" />
     <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
     <uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.MANAGE_ACCOUNTS"/>
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
     <uses-permission android:name="android.permission.RECORD_AUDIO"/>
     <uses-permission android:name="android.permission.USE_CREDENTIALS"/>
@@ skipping 20 matching lines @@
             <meta-data android:name="android.accounts.AccountAuthenticator"
                      android:resource="@xml/dummy_spnego_authenticator" />
         </service>
     </application>
 
     <instrumentation android:name="org.chromium.native_test.NativeTestInstrumentationTestRunner"
             android:targetPackage="org.chromium.native_test"
             android:label="Instrumentation entry point for org.chromium.native_test"/>
 
 </manifest>