Implement prediction_options.

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 65 matching lines @@
 // but it is destroyed on the IO thread when ProfileIOData goes away. All of
 // its core state and functionality happens on the IO thread. The only UI
 // methods are initialization / shutdown related (including preconnect
 // initialization), or convenience methods that internally forward calls to
 // the IO thread.
 class Predictor {
  public:
   // Enum describing when to allow network predictions based on connection type.
   // The same enum must be used by the platform-dependent components.
   // TODO(bnc): implement as per crbug.com/334602.
+  // NETWORK_PREDICTION_UNSET means that the old setting(s) should be observed.

[jkarlin, 2014/06/26 16:28:52]

Unclear what "the old settings" refers to here.

[Bence, 2014/06/26 20:02:06]

Done.

   enum NetworkPredictionOptions {
     NETWORK_PREDICTION_ALWAYS,
     NETWORK_PREDICTION_WIFI_ONLY,
-    NETWORK_PREDICTION_NEVER
+    NETWORK_PREDICTION_NEVER,
+    NETWORK_PREDICTION_UNSET,
   };
 
   // A version number for prefs that are saved. This should be incremented when
   // we change the format so that we discard old data.
   static const int kPredictorReferrerVersion;
 
   // Given that the underlying Chromium resolver defaults to a total maximum of
   // 8 paralell resolutions, we will avoid any chance of starving navigational
   // resolutions by limiting the number of paralell speculative resolutions.
   // This is used in the field trials and testing.
@@ skipping 514 matching lines @@
       PrefService* user_prefs,
       PrefService* local_state,
       IOThread* io_thread,
       net::URLRequestContextGetter* getter) OVERRIDE;
   virtual void ShutdownOnUIThread() OVERRIDE;
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PREDICTOR_H_