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

net/url_request/url_request_context_storage.h

Index: net/url_request/url_request_context_storage.h
diff --git a/net/url_request/url_request_context_storage.h b/net/url_request/url_request_context_storage.h
index f792d8ec2f6b892887311d782eaa4afaac2be9b6..bc040b2907d91c928dab15906db654d996dc3f48 100644
--- a/net/url_request/url_request_context_storage.h
+++ b/net/url_request/url_request_context_storage.h
@@ -41,10 +41,10 @@ class NET_EXPORT URLRequestContextStorage {
   ~URLRequestContextStorage();
 
   // These setters will set both the member variables and call the setter on the
-  // URLRequestContext object.
+  // URLRequestContext object. In all cases, ownership is passed to |this|.
 
   void set_net_log(NetLog* net_log);
-  void set_host_resolver(HostResolver* host_resolver);
+  void set_host_resolver(scoped_ptr<HostResolver> host_resolver);
   void set_cert_verifier(CertVerifier* cert_verifier);
   void set_server_bound_cert_service(
       ServerBoundCertService* server_bound_cert_service);