Don't clear the net predictors prefs on startup

chrome/browser/net/predictor.cc

Index: chrome/browser/net/predictor.cc
diff --git a/chrome/browser/net/predictor.cc b/chrome/browser/net/predictor.cc
index e81f4a83101834554d2121c676e51f18e02149f3..4e9440a831f780e7e7e3d4210ae541c915c33a18 100644
--- a/chrome/browser/net/predictor.cc
+++ b/chrome/browser/net/predictor.cc
@@ -157,16 +157,8 @@ void Predictor::InitNetworkPredictor(PrefService* user_prefs,
   // Gather the list of hostnames to prefetch on startup.
   std::vector<GURL> urls = GetPredictedUrlListAtStartup(user_prefs);
 
-  base::ListValue* referral_list =
-      static_cast<base::ListValue*>(user_prefs->GetList(
-          prefs::kDnsPrefetchingHostReferralList)->DeepCopy());
-
-  // Now that we have the statistics in memory, wipe them from the Preferences
-  // file. They will be serialized back on a clean shutdown. This way we only
-  // have to worry about clearing our in-memory state when Clearing Browsing
-  // Data.
-  user_prefs->ClearPref(prefs::kDnsPrefetchingStartupList);
-  user_prefs->ClearPref(prefs::kDnsPrefetchingHostReferralList);
+  const base::ListValue* referral_list =
+      user_prefs->GetList(prefs::kDnsPrefetchingHostReferralList);
 
   BrowserThread::PostTask(
       BrowserThread::IO,
@@ -626,12 +618,6 @@ void Predictor::DeserializeReferrers(const base::ListValue& referral_list) {
   }
 }
 
-void Predictor::DeserializeReferrersThenDelete(
-    base::ListValue* referral_list) {
-  DeserializeReferrers(*referral_list);
-  delete referral_list;
-}
-
 void Predictor::DiscardInitialNavigationHistory() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (initial_observer_.get())
@@ -640,7 +626,7 @@ void Predictor::DiscardInitialNavigationHistory() {
 
 void Predictor::FinalizeInitializationOnIOThread(
     const std::vector<GURL>& startup_urls,
-    base::ListValue* referral_list,
+    const base::ListValue* referral_list,
     IOThread* io_thread,
     ProfileIOData* profile_io_data) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
@@ -664,7 +650,7 @@ void Predictor::FinalizeInitializationOnIOThread(
   // Prefetch these hostnames on startup.
   DnsPrefetchMotivatedList(startup_urls, UrlInfo::STARTUP_LIST_MOTIVATED);
 
-  DeserializeReferrersThenDelete(referral_list);
+  DeserializeReferrers(*referral_list);
 
   LogStartupMetrics();
 }
@@ -912,6 +898,12 @@ bool Predictor::CanPreresolveAndPreconnect() const {
   }
 }
 
+void Predictor::ClearPrefsOnUIThread() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  user_prefs_->ClearPref(prefs::kDnsPrefetchingStartupList);
+  user_prefs_->ClearPref(prefs::kDnsPrefetchingHostReferralList);
+}
+
 enum SubresourceValue {
   PRECONNECTION,
   PRERESOLUTION,