Fix to ensure single instance of BrowserSettings

Change-Id: I696f3addecbac9674bfce9c1077257119fac9e02
diff --git a/src/com/android/browser/BrowserSettings.java b/src/com/android/browser/BrowserSettings.java
index ba827b9..2f93d57 100644
--- a/src/com/android/browser/BrowserSettings.java
+++ b/src/com/android/browser/BrowserSettings.java
@@ -131,8 +131,9 @@
 
     private static String sFactoryResetUrl;
 
-    public static void initialize(final Context context) {
-        sInstance = new BrowserSettings(context);
+    public static synchronized void initialize(final Context context) {
+        if (sInstance == null)
+            sInstance = new BrowserSettings(context);
     }
 
     public static BrowserSettings getInstance() {