Refactor Android's NetworckChangeNotifier.

net/android/network_change_notifier_factory.cc

Index: net/android/network_change_notifier_factory.cc
diff --git a/net/android/network_change_notifier_factory.cc b/net/android/network_change_notifier_factory.cc
index 82d2761394939abee7f235eec69fd26201a8dd1d..7e9a85f6494f95c84899126e99d1caf357e7113e 100644
--- a/net/android/network_change_notifier_factory.cc
+++ b/net/android/network_change_notifier_factory.cc
@@ -9,10 +9,20 @@
 namespace net {
 namespace android {
 
+namespace {
+NetworkChangeNotifier* g_instance = NULL;
+}
+
 NetworkChangeNotifierFactory::NetworkChangeNotifierFactory() {}
 
 net::NetworkChangeNotifier* NetworkChangeNotifierFactory::CreateInstance() {
-  return new NetworkChangeNotifier();
+  DCHECK(!g_instance);
+  g_instance = new NetworkChangeNotifier();
+  return g_instance;
+}
+
+NetworkChangeNotifier* NetworkChangeNotifierFactory::GetInstance() {
+  return g_instance;
 }
 
 }  // namespace android