[net] Change factory methods for HostResolver and HostCache to return a scoped_ptr

sync/tools/sync_listen_notifications.cc

Index: sync/tools/sync_listen_notifications.cc
diff --git a/sync/tools/sync_listen_notifications.cc b/sync/tools/sync_listen_notifications.cc
index 73d78e3b826ebb1cb1e413f7dff07226ab041aef..d8cc2131612a9f26e29c2660afaf09ddbbfbfdec 100644
--- a/sync/tools/sync_listen_notifications.cc
+++ b/sync/tools/sync_listen_notifications.cc
@@ -118,10 +118,7 @@ class MyTestURLRequestContext : public TestURLRequestContext {
  public:
   MyTestURLRequestContext() : TestURLRequestContext(true) {
     context_storage_.set_host_resolver(
-        net::CreateSystemHostResolver(
-            net::HostResolver::kDefaultParallelism,
-            net::HostResolver::kDefaultRetryAttempts,
-            NULL));
+        net::HostResolver::CreateDefaultResolver(NULL));
     context_storage_.set_transport_security_state(
         new net::TransportSecurityState());
     Init();