Don't clear the net predictors prefs on startup

chrome/browser/net/predictor.h

 // 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.
 
 // A Predictor object is instantiated once in the browser process, and manages
 // both preresolution of hostnames, as well as TCP/IP preconnection to expected
 // subresources.
 // Most hostname lists are provided by the renderer processes, and include URLs
 // that *might* be used in the near future by the browsing user.  One goal of
 // this class is to cause the underlying DNS structure to lookup a hostname
@@ skipping 140 matching lines @@
   // preconnect to the search server).
   void AnticipateOmniboxUrl(const GURL& url, bool preconnectable);
 
   // Preconnect a URL and all of its subresource domains.
   void PreconnectUrlAndSubresources(const GURL& url,
                                     const GURL& first_party_for_cookies);
 
   static std::vector<GURL> GetPredictedUrlListAtStartup(
       PrefService* user_prefs);
 
+  // Calls ClearPrefsOnUIThread and posts a task to the IO thread to
+  // DiscardAllResults.
+  void DiscardAllResultsAndClearPrefsOnUIThread();
+
+  // Clears the preferences used by the predictor. Must be called on the UI
+  // thread.
+  void ClearPrefsOnUIThread();
+
   static void set_max_queueing_delay(int max_queueing_delay_ms);
 
   static void set_max_parallel_resolves(size_t max_parallel_resolves);
 
   virtual void ShutdownOnUIThread();
 
   // ------------- End UI thread methods.
 
   // ------------- Start IO thread methods.
 
@@ skipping 31 matching lines @@
 
   // Construct a ListValue object that contains all the data in the referrers_
   // so that it can be persisted in a pref.
   void SerializeReferrers(base::ListValue* referral_list);
 
   // Process a ListValue that contains all the data from a previous reference
   // list, as constructed by SerializeReferrers(), and add all the identified
   // values into the current referrer list.
   void DeserializeReferrers(const base::ListValue& referral_list);
 
-  void DeserializeReferrersThenDelete(base::ListValue* referral_list);
-
   void DiscardInitialNavigationHistory();
 
   void FinalizeInitializationOnIOThread(
       const std::vector<GURL>& urls_to_prefetch,
-      base::ListValue* referral_list,
+      std::unique_ptr<base::ListValue> referral_list,
       IOThread* io_thread,
       ProfileIOData* profile_io_data);
 
   // During startup, we learn what the first N urls visited are, and then
   // resolve the associated hosts ASAP during our next startup.
   void LearnAboutInitialNavigation(const GURL& url);
 
   // Renderer bundles up list and sends to this browser API via IPC.
   // TODO(csharrison): Use a GURL vector instead to include port and scheme.
   void DnsPrefetchList(const std::vector<std::string>& hostnames);
@@ skipping 327 matching lines @@
 
  private:
   // These member functions return True for unittests.
   bool CanPrefetchAndPrerender() const override;
   bool CanPreresolveAndPreconnect() const override;
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PREDICTOR_H_