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

sync/tools/sync_client.cc

Index: sync/tools/sync_client.cc
diff --git a/sync/tools/sync_client.cc b/sync/tools/sync_client.cc
index 01da9831f10f613258257f6520719c3d9ee0807a..96be8a300c254bae465d1524d646e67c7eb919e8 100644
--- a/sync/tools/sync_client.cc
+++ b/sync/tools/sync_client.cc
@@ -105,10 +105,7 @@ 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();