Remove migrateNetworkPredictionPreferences().

chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java b/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
index 22a6cdbeb0626739292425a70a745863806fc497..0bd4962e347101556ffdeb443c93cd17d27e94f4 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
@@ -15,7 +15,6 @@ import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.device.DeviceClassManager;
-import org.chromium.chrome.browser.preferences.NetworkPredictionOptions;
 import org.chromium.chrome.browser.preferences.PrefServiceBridge;
 
 /**
@@ -26,11 +25,8 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
     static final String PREF_CRASH_DUMP_UPLOAD = "crash_dump_upload";
     static final String PREF_CRASH_DUMP_UPLOAD_NO_CELLULAR = "crash_dump_upload_no_cellular";
     private static final String PREF_NETWORK_PREDICTIONS = "network_predictions";

[newt (away), 2015/09/01 18:44:39]

also delete PREF_NETWORK_PREDICTIONS?

[Bence, 2015/09/01 20:39:59]

My understanding is that this is the new preference (the one the migration
routine sets if it wasn't set), and is still used in 
org.chromium.chrome.browser.preferences.privacy.PrivacyPreferences.onCreate and
org.chromium.chrome.browser.preferences.privacy.PrivacyPreferences.onPreferenceChange,
so it should not be deleted.

[newt (away), 2015/09/01 21:24:21]

Ah, right. Still, this constant can be removed as it's now unused.

[Bence, 2015/09/02 12:31:44]

Done.  Sorry, I didn't realize this definition is class scope, and it is defined
elsewhere for other user.  My apologies.

-    private static final String PREF_BANDWIDTH_OLD = "prefetch_bandwidth";
-    private static final String PREF_BANDWIDTH_NO_CELLULAR_OLD = "prefetch_bandwidth_no_cellular";
     private static final String PREF_METRICS_REPORTING = "metrics_reporting";
     private static final String PREF_CELLULAR_EXPERIMENT = "cellular_experiment";
-    private static final String ALLOW_PRERENDER_OLD = "allow_prefetch";
 
     private static PrivacyPreferencesManager sInstance;
 
@@ -68,109 +64,6 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
                 mCrashDumpNeverUpload);
     }
 
-    /**
-     * Migrate and delete old preferences.  Note that migration has to happen in Android-specific
-     * code because we need to access ALLOW_PRERENDER sharedPreference.
-     * TODO(bnc) https://crbug.com/394845. This change is planned for M38. After a year or so, it
-     * would be worth considering removing this migration code (also removing accessors in
-     * PrefServiceBridge and pref_service_bridge), and reverting to default for users
-     * who had set preferences but have not used Chrome for a year. This change would be subject to
-     * privacy review.
-     */
-    public void migrateNetworkPredictionPreferences() {
-        PrefServiceBridge prefService = PrefServiceBridge.getInstance();
-
-        // See if PREF_NETWORK_PREDICTIONS is an old boolean value.
-        boolean predictionOptionIsBoolean = false;
-        try {
-            mSharedPreferences.getString(PREF_NETWORK_PREDICTIONS, "");
-        } catch (ClassCastException ex) {
-            predictionOptionIsBoolean = true;
-        }
-
-        // Nothing to do if the user or this migration code has already set the new
-        // preference.
-        if (!predictionOptionIsBoolean
-                && prefService.networkPredictionOptionsHasUserSetting()) {
-            return;
-        }
-
-        // Nothing to do if the old preferences are unset.
-        if (!predictionOptionIsBoolean
-                && !mSharedPreferences.contains(PREF_BANDWIDTH_OLD)
-                && !mSharedPreferences.contains(PREF_BANDWIDTH_NO_CELLULAR_OLD)) {
-            return;
-        }
-
-        // Migrate if the old preferences are at their default values.
-        // (Note that for PREF_BANDWIDTH*, if the setting is default, then there is no way to tell
-        // whether the user has set it.)
-        final String prefBandwidthDefault = BandwidthType.PRERENDER_ON_WIFI.title();
-        final String prefBandwidth =
-                mSharedPreferences.getString(PREF_BANDWIDTH_OLD, prefBandwidthDefault);
-        boolean prefBandwidthNoCellularDefault = true;
-        boolean prefBandwidthNoCellular = mSharedPreferences.getBoolean(
-                PREF_BANDWIDTH_NO_CELLULAR_OLD, prefBandwidthNoCellularDefault);
-
-        if (!(prefBandwidthDefault.equals(prefBandwidth))
-                || (prefBandwidthNoCellular != prefBandwidthNoCellularDefault)) {
-            NetworkPredictionOptions newValue = NetworkPredictionOptions.DEFAULT;
-            // Observe PREF_BANDWIDTH on mobile network capable devices.
-            if (isMobileNetworkCapable()) {
-                if (mSharedPreferences.contains(PREF_BANDWIDTH_OLD)) {
-                    BandwidthType prefetchBandwidthTypePref = BandwidthType.getBandwidthFromTitle(

[newt (away), 2015/09/01 18:44:39]

Also delete BandwidthType.java.

[Bence, 2015/09/01 20:39:59]

Done.

-                            prefBandwidth);
-                    if (BandwidthType.NEVER_PRERENDER.equals(prefetchBandwidthTypePref)) {
-                        newValue = NetworkPredictionOptions.NETWORK_PREDICTION_NEVER;
-                    } else if (BandwidthType.PRERENDER_ON_WIFI.equals(prefetchBandwidthTypePref)) {
-                        newValue = NetworkPredictionOptions.NETWORK_PREDICTION_WIFI_ONLY;
-                    } else if (BandwidthType.ALWAYS_PRERENDER.equals(prefetchBandwidthTypePref)) {
-                        newValue = NetworkPredictionOptions.NETWORK_PREDICTION_ALWAYS;
-                    }
-                }
-            // Observe PREF_BANDWIDTH_NO_CELLULAR on devices without mobile network.
-            } else {
-                if (mSharedPreferences.contains(PREF_BANDWIDTH_NO_CELLULAR_OLD)) {
-                    if (prefBandwidthNoCellular) {
-                        newValue = NetworkPredictionOptions.NETWORK_PREDICTION_WIFI_ONLY;
-                    } else {
-                        newValue = NetworkPredictionOptions.NETWORK_PREDICTION_NEVER;
-                    }
-                }
-            }
-            // But disable after all if kNetworkPredictionEnabled was disabled by the user.
-            if (prefService.networkPredictionEnabledHasUserSetting()
-                    && !prefService.getNetworkPredictionEnabledUserPrefValue()) {
-                newValue = NetworkPredictionOptions.NETWORK_PREDICTION_NEVER;
-            }
-            // Save new value in Chrome PrefService.
-            prefService.setNetworkPredictionOptions(newValue);
-        }
-
-        // Delete old sharedPreferences.
-        SharedPreferences.Editor sharedPreferencesEditor = mSharedPreferences.edit();
-        // Delete PREF_BANDWIDTH and PREF_BANDWIDTH_NO_CELLULAR: just migrated these options.
-        if (mSharedPreferences.contains(PREF_BANDWIDTH_OLD)) {
-            sharedPreferencesEditor.remove(PREF_BANDWIDTH_OLD);
-        }
-        if (mSharedPreferences.contains(PREF_BANDWIDTH_NO_CELLULAR_OLD)) {
-            sharedPreferencesEditor.remove(PREF_BANDWIDTH_NO_CELLULAR_OLD);
-        }
-        // Also delete ALLOW_PRERENDER, which was updated based on PREF_BANDWIDTH[_NO_CELLULAR] and
-        // network connectivity type, therefore does not carry additional information.
-        if (mSharedPreferences.contains(ALLOW_PRERENDER_OLD)) {
-            sharedPreferencesEditor.remove(ALLOW_PRERENDER_OLD);
-        }
-        // Delete bool PREF_NETWORK_PREDICTIONS so that string values can be stored. Note that this
-        // SharedPreference carries no information, because it used to be overwritten by
-        // kNetworkPredictionEnabled on startup, and now it is overwritten by
-        // kNetworkPredictionOptions on startup.
-        if (mSharedPreferences.contains(PREF_NETWORK_PREDICTIONS)) {
-            sharedPreferencesEditor.remove(PREF_NETWORK_PREDICTIONS);
-        }
-        sharedPreferencesEditor.apply();
-    }
-
     private NetworkInfo getActiveNetworkInfo() {
         ConnectivityManager connectivityManager =
                 (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
@@ -199,9 +92,8 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
      * @return Whether prerendering should be allowed.
      */
     public boolean shouldPrerender() {
-        if (!DeviceClassManager.enablePrerendering()) return false;
-        migrateNetworkPredictionPreferences();
-        return PrefServiceBridge.getInstance().canPredictNetworkActions();
+        return DeviceClassManager.enablePrerendering()
+                && PrefServiceBridge.getInstance().canPredictNetworkActions();
     }
 
     /**