Update "Predict network actions" UI setting.

chrome/browser/net/prediction_options.cc

Index: chrome/browser/net/prediction_options.cc
diff --git a/chrome/browser/net/prediction_options.cc b/chrome/browser/net/prediction_options.cc
index 34fc98894e72e5c40f5ac2b8b2482c13378d0883..8afc04809ce6541d6bd9440f3f82318aa674f02a 100644
--- a/chrome/browser/net/prediction_options.cc
+++ b/chrome/browser/net/prediction_options.cc
@@ -46,6 +46,33 @@ void RegisterPredictionOptionsProfilePrefs(
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
 }
 
+void MigrateNetworkPredictionUserPrefs(PrefService* pref_service) {
+  const PrefService::Preference* network_prediction_options =
+      pref_service->FindPreference(prefs::kNetworkPredictionOptions);
+  DCHECK(network_prediction_options);
+
+  // Nothing to do if the user or this migration code has already set the new
+  // preference.
+  if (network_prediction_options->HasUserSetting())

[Bernhard Bauer, 2014/08/07 08:32:17]

You could directly use pref_service->IsUserModifiablePreference(...).

[bartfab (slow), 2014/08/07 12:17:06]

HasUserSetting() and IsUserModifiablePreference() are not the same thing at all.
The former tells you whether there is a user-set value, even if that value may
be currently shadowed by policy. The latter tells you whether policy is
currently in charge, irrespective of whether there is a user-set value or not.

The current code is correct - if there is a user-set value already, do nothing.

[Bernhard Bauer, 2014/08/07 12:24:12]

Urr, I meant pref_service->GetUserPrefValue().

[Bence, 2014/08/07 13:50:01]

Done.

+    return;
+
+  const PrefService::Preference* network_prediction_enabled =
+      pref_service->FindPreference(prefs::kNetworkPredictionEnabled);
+  DCHECK(network_prediction_enabled);
+
+  // Nothing to do if the user has not set the old preference.
+  if (!network_prediction_enabled->HasUserSetting())
+    return;
+
+  bool value;

[battre, 2014/08/07 07:56:52]

please initialize.

[Bence, 2014/08/07 13:50:01]

Done.

+  if (network_prediction_enabled->GetUserValue()->GetAsBoolean(&value)) {
+    pref_service->SetInteger(
+        prefs::kNetworkPredictionOptions,
+        value ? chrome_browser_net::NETWORK_PREDICTION_WIFI_ONLY
+              : chrome_browser_net::NETWORK_PREDICTION_NEVER);
+  }
+}
+
 bool CanPredictNetworkActionsIO(ProfileIOData* profile_io_data) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
   DCHECK(profile_io_data);