NULL check before deref, not after

chrome/browser/prerender/prerender_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prerender/prerender_manager.h"
 
 #include <algorithm>
 #include <functional>
 #include <string>
 #include <vector>
@@ skipping 444 matching lines @@
       // TODO(tburkard): I'd like to DCHECK that we are actually prerendering.
       // However, what if new conditions are added and
       // NeedMatchCompleteDummyForFinalStatus, is not being updated.  Not sure
       // what's the best thing to do here.  For now, I will just check whether
       // we are actually prerendering.
       entry->set_match_complete_status(
           PrerenderContents::MATCH_COMPLETE_REPLACED);
       PrerenderContents* dummy_replacement_prerender_contents =
           CreatePrerenderContents(entry->prerender_url(), entry->referrer(),
                                   entry->origin(), entry->experiment_id());
+      DCHECK(dummy_replacement_prerender_contents);
       dummy_replacement_prerender_contents->MakeIntoDummyReplacementOf(entry);
-      DCHECK(dummy_replacement_prerender_contents);
 
       dummy_replacement_prerender_contents->set_match_complete_status(
           PrerenderContents::MATCH_COMPLETE_REPLACEMENT_PENDING);
       DCHECK(dummy_replacement_prerender_contents->Init());
       dummy_replacement_prerender_contents->
           AddAliasURLsFromOtherPrerenderContents(entry);
       dummy_replacement_prerender_contents->set_match_complete_status(
           PrerenderContents::MATCH_COMPLETE_REPLACEMENT);
 
       it->get()->contents_ = dummy_replacement_prerender_contents;
@@ skipping 747 matching lines @@
   if (!render_process_host || !render_process_host->GetBrowserContext())
     return NULL;
   Profile* profile = Profile::FromBrowserContext(
       render_process_host->GetBrowserContext());
   if (!profile)
     return NULL;
   return PrerenderManagerFactory::GetInstance()->GetForProfile(profile);
 }
 
 }  // namespace prerender