Prerender: Allow on low end devices for ORIGIN_OFFLINE

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 <stddef.h>
 
 #include <algorithm>
 #include <functional>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
+#include "base/sys_info.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/timer/elapsed_timer.h"
 #include "base/values.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/net/prediction_options.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
 #include "chrome/browser/prerender/prerender_handle.h"
@@ skipping 806 matching lines @@
     PrerenderData* data = it->get();
     if (data == prerender_data) {
       data->set_expiry_time(std::min(data->expiry_time(),
                                      GetExpiryTimeForNavigatedAwayPrerender()));
       SortActivePrerenders();
       return;
     }
   }
 }
 
+bool PrerenderManager::IsLowEndDevice() const {
+  return base::SysInfo::IsLowEndDevice();
+}
+
 std::unique_ptr<PrerenderHandle> PrerenderManager::AddPrerender(
     Origin origin,
     const GURL& url_arg,
     const content::Referrer& referrer,
     const gfx::Size& size,
     SessionStorageNamespace* session_storage_namespace) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
+  // Allow only Requests for offlining on low end devices, the lifetime of
+  // those prerenders is managed by the offliner.
+  if (IsLowEndDevice() && origin != ORIGIN_OFFLINE)
+    return nullptr;
+
   if ((origin == ORIGIN_LINK_REL_PRERENDER_CROSSDOMAIN ||
        origin == ORIGIN_LINK_REL_PRERENDER_SAMEDOMAIN) &&
       IsGoogleSearchResultURL(referrer.url)) {
     origin = ORIGIN_GWS_PRERENDER;
   }
 
   GURL url = url_arg;
   GURL alias_url;
   if (IsControlGroup() && MaybeGetQueryStringBasedAliasURL(url, &alias_url))
     url = alias_url;
@@ skipping 416 matching lines @@
   DCHECK_EQ(1u, erased);
 }
 
 void PrerenderManager::SetPrerenderContentsFactoryForTest(
     PrerenderContents::Factory* prerender_contents_factory) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   prerender_contents_factory_.reset(prerender_contents_factory);
 }
 
 }  // namespace prerender