[Android WebView] Implement support for Network Information API and enable it.

android_webview/browser/net/aw_network_change_notifier_factory.cc

+// Copyright 2016 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 "android_webview/browser/net/aw_network_change_notifier_factory.h"
+
+#include "android_webview/browser/net/aw_network_change_notifier.h"
+
+namespace android_webview {
+
+AwNetworkChangeNotifierFactory::AwNetworkChangeNotifierFactory() {}
+
+AwNetworkChangeNotifierFactory::~AwNetworkChangeNotifierFactory() {}
+
+net::NetworkChangeNotifier* AwNetworkChangeNotifierFactory::CreateInstance() {
+  return new AwNetworkChangeNotifier(&delegate_);
+}
+
+}  // namespace android_webview