[Android] Migrate javascript settings to a content setting from a pref.

chrome/android/java/src/org/chromium/chrome/browser/preferences/PrefServiceBridge.java

 // 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.
 
 package org.chromium.chrome.browser.preferences;
 
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
 import android.text.TextUtils;
+import android.util.Log;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.ThreadUtils;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService;
 
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * PrefServiceBridge is a singleton which provides access to some native preferences. Ideally
  * preferences should be grouped with their relevant functionality but this is a grab-bag for other
  * preferences.
  */
 public final class PrefServiceBridge {
 
     // Does not need sync with native; used for the popup settings check
     public static final String EXCEPTION_SETTING_ALLOW = "allow";
     public static final String EXCEPTION_SETTING_BLOCK = "block";
     public static final String EXCEPTION_SETTING_DEFAULT = "default";
 
     // These values must match the native enum values in
     // SupervisedUserURLFilter::FilteringBehavior
     public static final int SUPERVISED_USER_FILTERING_ALLOW = 0;
     public static final int SUPERVISED_USER_FILTERING_WARN = 1;
     public static final int SUPERVISED_USER_FILTERING_BLOCK = 2;
 
+    private static final String MIGRATION_PREF_KEY = "PrefMigrationVersion";
+    private static final int MIGRATION_CURRENT_VERSION = 1;
+
     private static String sProfilePath;
 
     // Object to notify when "clear browsing data" completes.
     private OnClearBrowsingDataListener mClearBrowsingDataListener;
     private static final String LOG_TAG = "PrefServiceBridge";
 
     // Constants related to the Contextual Search preference.
     private static final String CONTEXTUAL_SEARCH_DISABLED = "false";
     private static final String CONTEXTUAL_SEARCH_ENABLED = "true";
 
@@ skipping 92 matching lines @@
     }
 
     /**
      * @return Whether the preferences have been initialized.
      */
     public static boolean isInitialized() {
         return sInstance != null;
     }
 
     /**
+     * Migrates (synchronously) the preferences to the most recent version.
+     */
+    public void migratePreferences(Context context) {
+        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
+        int currentVersion = preferences.getInt(MIGRATION_PREF_KEY, 0);
+        if (currentVersion > MIGRATION_CURRENT_VERSION) {
+            Log.e(LOG_TAG, "Saved preferences version is newer than supported.  Attempting to "
+                    + "run an older version of Chrome without clearing data is unsupported and "
+                    + "the results may be unpredictable.");
+        }
+        if (currentVersion == MIGRATION_CURRENT_VERSION) return;

[newt (away), 2015/02/12 01:25:02]

nit: I'd put this if check first, since it's the common/quick case

[Ted C, 2015/02/12 17:18:19]

Done.

+
+        if (currentVersion <= 0) {
+            nativeMigrateJavascriptPreference();
+        }
+        preferences.edit().putInt(MIGRATION_PREF_KEY, MIGRATION_CURRENT_VERSION).commit();
+    }
+
+    /**
      * Returns the path to the user's profile directory via a callback. The callback may be
      * called synchronously or asynchronously.
      */
     public void getProfilePath(ProfilePathCallback callback) {
         if (!TextUtils.isEmpty(sProfilePath)) {
             callback.onGotProfilePath(sProfilePath);
         } else {
             nativeGetProfilePath(callback);
         }
     }
@@ skipping 583 matching lines @@
     private native boolean nativeGetCrashReportManaged();
     private native boolean nativeGetIncognitoModeEnabled();
     private native boolean nativeGetIncognitoModeManaged();
     private native boolean nativeGetPrintingEnabled();
     private native boolean nativeGetPrintingManaged();
     private native boolean nativeGetForceSafeSearch();
     private native void nativeSetTranslateEnabled(boolean enabled);
     private native void nativeResetTranslateDefaults();
     private native boolean nativeGetJavaScriptEnabled();
     private native void nativeSetJavaScriptEnabled(boolean enabled);
+    private native void nativeMigrateJavascriptPreference();
     private native void nativeClearBrowsingData(boolean history, boolean cache,
             boolean cookiesAndSiteData, boolean passwords, boolean formData);
     private native void nativeSetAllowCookiesEnabled(boolean allow);
     private native void nativeSetBlockThirdPartyCookiesEnabled(boolean enabled);
     private native void nativeSetDoNotTrackEnabled(boolean enabled);
     private native void nativeSetRememberPasswordsEnabled(boolean allow);
     private native void nativeSetProtectedMediaIdentifierEnabled(boolean enabled);
     private native boolean nativeGetAllowLocationEnabled();
     private native boolean nativeGetPushNotificationsEnabled();
     private native void nativeSetAllowLocationEnabled(boolean allow);
@@ skipping 30 matching lines @@
     private native void nativeResetAcceptLanguages(String defaultLocale);
     private native String nativeGetSyncLastAccountName();
     private native String nativeGetSupervisedUserCustodianName();
     private native String nativeGetSupervisedUserCustodianEmail();
     private native String nativeGetSupervisedUserCustodianProfileImageURL();
     private native int nativeGetDefaultSupervisedUserFilteringBehavior();
     private native String nativeGetSupervisedUserSecondCustodianName();
     private native String nativeGetSupervisedUserSecondCustodianEmail();
     private native String nativeGetSupervisedUserSecondCustodianProfileImageURL();
 }