Do conservative prerendering based on the LocalPredictor in Dev/Canary.

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 362 matching lines @@
 PrerenderHandle* PrerenderManager::AddPrerenderFromOmnibox(
     const GURL& url,
     SessionStorageNamespace* session_storage_namespace,
     const gfx::Size& size) {
   if (!IsOmniboxEnabled(profile_))
     return NULL;
   return AddPrerender(ORIGIN_OMNIBOX, -1, url, content::Referrer(), size,
                       session_storage_namespace);
 }
 
+PrerenderHandle* PrerenderManager::AddPrerenderFromLocalPredictor(
+    const GURL& url,
+    SessionStorageNamespace* session_storage_namespace,
+    const gfx::Size& size) {
+  return AddPrerender(ORIGIN_LOCAL_PREDICTOR, -1, url, content::Referrer(),
+                      size, session_storage_namespace);
+}
+
 void PrerenderManager::DestroyPrerenderForRenderView(
     int process_id, int view_id, FinalStatus final_status) {
   DCHECK(CalledOnValidThread());
   if (PrerenderData* prerender_data =
           FindPrerenderDataForChildAndRoute(process_id, view_id)) {
     prerender_data->contents()->Destroy(final_status);
   }
 }
 
 void PrerenderManager::CancelAllPrerenders() {
@@ skipping 725 matching lines @@
     // by a navigation and is unlikely to be the same site.
     RecordFinalStatus(origin, experiment, FINAL_STATUS_RATE_LIMIT_EXCEEDED);
     return NULL;
   }
 
   PrerenderContents* prerender_contents = CreatePrerenderContents(
       url, referrer, origin, experiment);
   DCHECK(prerender_contents);
   active_prerenders_.push_back(
       new PrerenderData(this, prerender_contents,
-                        GetExpiryTimeForNewPrerender()));
+                        GetExpiryTimeForNewPrerender(origin)));
   if (!prerender_contents->Init()) {
     DCHECK(active_prerenders_.end() ==
            FindIteratorForPrerenderContents(prerender_contents));
     return NULL;
   }
 
   histograms_->RecordPrerenderStarted(origin);
   DCHECK(!prerender_contents->prerendering_has_started());
 
   PrerenderHandle* prerender_handle =
@@ skipping 56 matching lines @@
   to_delete_prerenders_.clear();
 }
 
 void PrerenderManager::PostCleanupTask() {
   DCHECK(CalledOnValidThread());
   MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&PrerenderManager::PeriodicCleanup, AsWeakPtr()));
 }
 
-base::TimeTicks PrerenderManager::GetExpiryTimeForNewPrerender() const {
-  return GetCurrentTimeTicks() + config_.time_to_live;
+base::TimeTicks PrerenderManager::GetExpiryTimeForNewPrerender(
+    Origin origin) const {
+  base::TimeDelta ttl = config_.time_to_live;
+  if (origin == ORIGIN_LOCAL_PREDICTOR)
+    ttl = base::TimeDelta::FromSeconds(180);
+  return GetCurrentTimeTicks() + ttl;
 }
 
 base::TimeTicks PrerenderManager::GetExpiryTimeForNavigatedAwayPrerender()
     const {
   return GetCurrentTimeTicks() + config_.abandon_time_to_live;
 }
 
 void PrerenderManager::DeleteOldEntries() {
   DCHECK(CalledOnValidThread());
   while (!active_prerenders_.empty()) {
@@ skipping 308 matching lines @@
     logged_in_state_->erase(domain_key);
 }
 
 void PrerenderManager::LoggedInPredictorDataReceived(
     scoped_ptr<LoggedInStateMap> new_map) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   logged_in_state_.swap(new_map);
 }
 
 }  // namespace prerender