[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 5a832c2d89adc4215221b61ed5153973b280cb9b..80ca5e4a13c7a9829c838983a33e21a7cab2b02a 100644
--- a/sync/tools/sync_listen_notifications.cc
+++ b/sync/tools/sync_listen_notifications.cc
@@ -117,10 +117,7 @@ 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();