Have Frame::loader() return a reference

Source/core/loader/Prerenderer.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 64 matching lines @@
 
 PassRefPtr<Prerender> Prerenderer::render(PrerenderClient* prerenderClient, const KURL& url)
 {
     // Prerenders are unlike requests in most ways (for instance, they pass down fragments, and they don't return data),
     // but they do have referrers.
     const ReferrerPolicy referrerPolicy = document()->referrerPolicy();
 
     if (!document()->frame())
         return 0;
 
-    const String referrer = SecurityPolicy::generateReferrerHeader(referrerPolicy, url, document()->frame()->loader()->outgoingReferrer());
+    const String referrer = SecurityPolicy::generateReferrerHeader(referrerPolicy, url, document()->frame()->loader().outgoingReferrer());
 
     RefPtr<Prerender> prerender = Prerender::create(prerenderClient, url, referrer, referrerPolicy);
 
     if (client())
         client()->willAddPrerender(prerender.get());
     prerender->add();
 
     // FIXME: This prerender isn't released until page unload, but it may be canceled before then. It should be released in that case.
     m_activePrerenders.append(prerender);
     return prerender;
@@ skipping 19 matching lines @@
     if (!m_initializedClient) {
         // We can't initialize the client in our contructor, because the platform might not have
         // provided our supplement by then.
         m_initializedClient = true;
         m_client = PrerendererClient::from(document()->page());
     }
     return m_client;
 }
 
 }