Enable TCP preconnect and DNS preresolve on cellular.

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 417 matching lines @@
   // Only for testing;
   size_t peak_pending_lookups() const { return peak_pending_lookups_; }
 
   // If a proxy advisor is defined, let it know that |url| will be prefetched or
   // preconnected to. Can be called on either UI or IO threads and will post to
   // the IO thread if necessary, invoking AdviseProxyOnIOThread().
   void AdviseProxy(const GURL& url,
                    UrlInfo::ResolutionMotivation motivation,
                    bool is_preconnect);
 
-  // There two members call the corresponding global functions in
+  // These four members call the corresponding global functions in
   // prediction_options.cc.
   virtual bool CanPredictNetworkActionsUI();
   virtual bool CanPredictNetworkActionsIO();
+  virtual bool CanPreconnectUI();
+  virtual bool CanPreconnectIO();

[mmenke, 2014/08/08 16:05:42]

nit:  All 4 of these should be const.

[Bence, 2014/08/08 20:10:03]

Done.

 
   // ------------- Start IO thread methods.
 
   // Perform actual resolution or preconnection to subresources now.  This is
   // an internal worker method that is reached via a post task from
   // PredictFrameSubresources().
   void PrepareFrameSubresources(const GURL& url,
                                 const GURL& first_party_for_cookies);
 
   // Access method for use by async lookup request to pass resolution result.
@@ skipping 154 matching lines @@
       : Predictor(preconnect_enabled, predictor_enabled) {}
   virtual ~SimplePredictor() {}
   virtual void InitNetworkPredictor(
       PrefService* user_prefs,
       PrefService* local_state,
       IOThread* io_thread,
       net::URLRequestContextGetter* getter,
       ProfileIOData* profile_io_data) OVERRIDE;
   virtual void ShutdownOnUIThread() OVERRIDE;
  private:
-  // There member functions return True for unittests.
+  // These member functions return True for unittests.
   virtual bool CanPredictNetworkActionsUI() OVERRIDE;
   virtual bool CanPredictNetworkActionsIO() OVERRIDE;
+  virtual bool CanPreconnectUI() OVERRIDE;
+  virtual bool CanPreconnectIO() OVERRIDE;
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PREDICTOR_H_