Add a field trial to disable deferred committing of cookie changes

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 1300 matching lines @@
   // Check if enough time has passed since the last prerender.
   if (!DoesRateLimitAllowPrerender(origin)) {
     // Cancel the prerender. We could add it to the pending prerender list but
     // this doesn't make sense as the next prerender request will be triggered
     // by a navigation and is unlikely to be the same site.
     RecordFinalStatusWithoutCreatingPrerenderContents(
         url, origin, experiment, FINAL_STATUS_RATE_LIMIT_EXCEEDED);
     return NULL;
   }
 
-  if (!cookie_store_loaded()) {
+  if (IsPrerenderCookieStoreEnabled() && !cookie_store_loaded()) {
     // Only prerender if the cookie store for this profile has been loaded.
     // This is required by PrerenderCookieMonster.
     RecordFinalStatusWithoutCreatingPrerenderContents(
         url, origin, experiment, FINAL_STATUS_COOKIE_STORE_NOT_LOADED);
     return NULL;
   }
 
   PrerenderContents* prerender_contents = CreatePrerenderContents(
       url, referrer, origin, experiment);
   DCHECK(prerender_contents);
@@ skipping 11 matching lines @@
 
   PrerenderHandle* prerender_handle =
       new PrerenderHandle(active_prerenders_.back());
   SortActivePrerenders();
 
   last_prerender_start_time_ = GetCurrentTimeTicks();
 
   gfx::Size contents_size =
       size.IsEmpty() ? config_.default_tab_bounds.size() : size;
 
-  net::URLRequestContextGetter* request_context = GetURLRequestContext();
+  net::URLRequestContextGetter* request_context =
+      (IsPrerenderCookieStoreEnabled() ? GetURLRequestContext() : NULL);
 
   prerender_contents->StartPrerendering(process_id, contents_size,
                                         session_storage_namespace,
                                         request_context);
 
   DCHECK(IsControlGroup(experiment) ||
          prerender_contents->prerendering_has_started() ||
          (origin == ORIGIN_LOCAL_PREDICTOR &&
           IsLocalPredictorPrerenderAlwaysControlEnabled()));
 
@@ skipping 526 matching lines @@
 
 void PrerenderManager::AddPrerenderProcessHost(
     content::RenderProcessHost* process_host) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(prerender_process_hosts_.find(process_host) ==
          prerender_process_hosts_.end());
   prerender_process_hosts_.insert(process_host);
   process_host->AddObserver(this);
 }
 
-bool PrerenderManager::IsProcessPrerendering(
+bool PrerenderManager::MayReuseProcessHost(
     content::RenderProcessHost* process_host) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  return (prerender_process_hosts_.find(process_host) !=
+  // If prerender cookie stores are disabled, there is no need to require
+  // isolated prerender processes.
+  if (!IsPrerenderCookieStoreEnabled())
+    return true;
+  return (prerender_process_hosts_.find(process_host) ==
           prerender_process_hosts_.end());
 }
 
 void PrerenderManager::RenderProcessHostDestroyed(
     content::RenderProcessHost* host) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   prerender_process_hosts_.erase(host);
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&PrerenderTracker::RemovePrerenderCookieStoreOnIOThread,
                  base::Unretained(prerender_tracker()), host->GetID(), false));
 }
 
 }  // namespace prerender