Enable TCP preconnect and DNS preresolve on cellular.

chrome/browser/net/prediction_options.cc

 // Copyright 2014 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/net/prediction_options.h"
 
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/common/pref_names.h"
@@ skipping 16 matching lines @@
     case chrome_browser_net::NETWORK_PREDICTION_NEVER:
       return false;
     case chrome_browser_net::NETWORK_PREDICTION_UNSET:
       return NetworkPredictionEnabled;
     default:
       NOTREACHED() << "Unknown kNetworkPredictionOptions value.";
       return false;
   }
 }
 
+bool CanPreconnect(int NetworkPredictionOptions,
+                   bool NetworkPredictionEnabled) {

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

These should be named network_prediction_options and network_prediction_enabled.
 Same goes for the above function.

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

Done.

+  switch (NetworkPredictionOptions) {
+    case chrome_browser_net::NETWORK_PREDICTION_ALWAYS:
+      return true;
+    // We allow TCP preconnect and DNS preresolution even on cellular networks
+    // if the user setting is WIFI_ONLY.

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

nit:  Shouldn't use we in comments, since it's ambiguous (We the programmers, we
google, we meaning the program, etc).

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

Done.

+    case chrome_browser_net::NETWORK_PREDICTION_WIFI_ONLY:
+      return true;
+    case chrome_browser_net::NETWORK_PREDICTION_NEVER:
+      return false;
+    case chrome_browser_net::NETWORK_PREDICTION_UNSET:
+      return NetworkPredictionEnabled;
+    default:
+      NOTREACHED() << "Unknown kNetworkPredictionOptions value.";
+      return false;
+  }
+}
+
 }  // namespace
 
 namespace chrome_browser_net {
 
 void RegisterPredictionOptionsProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterIntegerPref(
       prefs::kNetworkPredictionOptions,
       chrome_browser_net::NETWORK_PREDICTION_UNSET,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
 }
 
 bool CanPredictNetworkActionsIO(ProfileIOData* profile_io_data) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   DCHECK(profile_io_data);
 
   return CanPredictNetworkActions(
       profile_io_data->network_prediction_options()->GetValue(),
       profile_io_data->network_prediction_enabled()->GetValue());
 }
 
 bool CanPredictNetworkActionsUI(PrefService* prefs) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(prefs);
   return CanPredictNetworkActions(
       prefs->GetInteger(prefs::kNetworkPredictionOptions),
       prefs->GetBoolean(prefs::kNetworkPredictionEnabled));
 }
 
+bool CanPreconnectIO(ProfileIOData* profile_io_data) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+  DCHECK(profile_io_data);
+

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

optional nit:  The two IO thread functions have blank lines here, the two UI
thread ones do not.  I suggest being uniform about the decision, since the
functions are all so similar.  I'm fine either way.

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

Done.

+  return CanPreconnect(
+      profile_io_data->network_prediction_options()->GetValue(),
+      profile_io_data->network_prediction_enabled()->GetValue());
+}
+
+bool CanPreconnectUI(PrefService* prefs) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  DCHECK(prefs);
+  return CanPreconnect(prefs->GetInteger(prefs::kNetworkPredictionOptions),
+                       prefs->GetBoolean(prefs::kNetworkPredictionEnabled));
+}
+
 }  // namespace chrome_browser_net