Increase prerender max-age limit to 30 seconds from 20 seconds.

chrome/browser/prerender/prerender_manager.cc

 // Copyright (c) 2011 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 "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/browser/browser_thread.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/render_process_host.h"
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 #include "content/browser/tab_contents/render_view_host_manager.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/common/notification_service.h"
 #include "content/common/view_messages.h"
 #include "googleurl/src/url_parse.h"
 #include "googleurl/src/url_canon.h"
 #include "googleurl/src/url_util.h"
 
 namespace prerender {
 
+namespace {
+
+// Default maximum permitted elements to prerender.
+const unsigned int kDefaultMaxPrerenderElements = 1;
+
+// Default maximum age a prerendered element may have, in seconds.
+const int kDefaultMaxPrerenderAgeSeconds = 30;
+
+// Time window for which we will record windowed PLT's from the last
+// observed link rel=prefetch tag.
+const int kWindowDurationSeconds = 30;
+
+// Time interval at which periodic cleanups are performed.
+const int kPeriodicCleanupIntervalMs = 1000;
+
+// Time interval before a new prerender is allowed.
+const int kMinTimeBetweenPrerendersMs = 500;
+
+}  // namespace
+
 // static
 int PrerenderManager::prerenders_per_session_count_ = 0;
 
 // static
 base::TimeTicks PrerenderManager::last_prefetch_seen_time_;
 
 // static
 PrerenderManager::PrerenderManagerMode PrerenderManager::mode_ =
     PRERENDER_MODE_ENABLED;
 
@@ skipping 558 matching lines @@
 
 bool PrerenderManager::IsTabContentsPrerendered(TabContents* tc) const {
   return prerendered_tc_set_.count(tc) > 0;
 }
 
 bool PrerenderManager::WouldTabContentsBePrerendered(TabContents* tc) const {
   return would_be_prerendered_tc_set_.count(tc) > 0;
 }
 
 }  // namespace prerender