Prevent double inialization of DOMUI pref handlers

chrome/browser/dom_ui/options/options_ui.h

Index: chrome/browser/dom_ui/options/options_ui.h
diff --git a/chrome/browser/dom_ui/options/options_ui.h b/chrome/browser/dom_ui/options/options_ui.h
index ad1007de07c1ffb82290b34393980bb807adf0d6..9ca0ff419395085b025a576587f1f1a047e0159c 100644
--- a/chrome/browser/dom_ui/options/options_ui.h
+++ b/chrome/browser/dom_ui/options/options_ui.h
@@ -53,6 +53,7 @@ class OptionsPageUIHandler : public DOMMessageHandler,
   virtual void GetLocalizedValues(DictionaryValue* localized_strings) = 0;
 
   // Initialize the page.  Called once the DOM is available for manipulation.
+  // This will be called only once.
   virtual void Initialize() {}
 
   // Uninitializes the page.  Called just before the object is destructed.
@@ -91,6 +92,8 @@ class OptionsUI : public DOMUI {
   void AddOptionsPageUIHandler(DictionaryValue* localized_strings,
                                OptionsPageUIHandler* handler);
 
+  bool initialized_handlers_;
+
   DISALLOW_COPY_AND_ASSIGN(OptionsUI);
 };