[Extensions] Fix chrome url override settings

chrome/browser/extensions/extension_web_ui.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_WEB_UI_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_WEB_UI_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 30 matching lines @@
 
   virtual extensions::BookmarkManagerPrivateDragEventRouter*
       bookmark_manager_private_drag_event_router();
 
   // BrowserURLHandler
   static bool HandleChromeURLOverride(GURL* url,
                                       content::BrowserContext* browser_context);
   static bool HandleChromeURLOverrideReverse(
       GURL* url, content::BrowserContext* browser_context);
 
-  // Register and unregister a dictionary of one or more overrides.
-  // Page names are the keys, and chrome-extension: URLs are the values.
-  // (e.g. { "newtab": "chrome-extension://<id>/my_new_tab.html" }
-  static void RegisterChromeURLOverrides(Profile* profile,
+  // Initialize the Chrome URL overrides. This must happen *before* any further
+  // calls for URL overrides!
+  static void InitializeChromeURLOverrides(Profile* profile);
+
+  // Validate the Chrome URL overrides, ensuring that each is valid and points
+  // to an existing extension. To be called once all extensions are loaded.
+  static void ValidateChromeURLOverrides(Profile* profile);
+
+  // Add new Chrome URL overrides. If an entry exists, it is marked as active.
+  // If one doesn't exist, it is added at the beginning of the list of
+  // overrides (meaning it has priority).
+  static void RegisterOrActivateChromeURLOverrides(
+      Profile* profile,
       const extensions::URLOverrides::URLOverrideMap& overrides);
-  static void UnregisterChromeURLOverrides(Profile* profile,
+
+  // Deactivate overrides without removing them from the list or modifying their
+  // positions in the list.
+  static void DeactivateChromeURLOverrides(
+      Profile* profile,
       const extensions::URLOverrides::URLOverrideMap& overrides);
-  static void UnregisterChromeURLOverride(const std::string& page,
-                                          Profile* profile,
-                                          const base::Value* override);
+
+  // Completely unregister overrides, removing them from the list.
+  static void UnregisterChromeURLOverrides(
+      Profile* profile,
+      const extensions::URLOverrides::URLOverrideMap& overrides);
 
   // Called from BrowserPrefs
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Get the favicon for the extension by getting an icon from the manifest.
   // Note. |callback| is always run asynchronously.
   static void GetFaviconForURL(
       Profile* profile,
       const GURL& page_url,
       const favicon_base::FaviconResultsCallback& callback);
 
  private:
   // Unregister the specified override, and if it's the currently active one,
   // ensure that something takes its place.
   static void UnregisterAndReplaceOverride(const std::string& page,
                                            Profile* profile,
                                            base::ListValue* list,
                                            const base::Value* override);
 
   // TODO(aa): This seems out of place. Why is it not with the event routers for
   // the other extension APIs?
   scoped_ptr<extensions::BookmarkManagerPrivateDragEventRouter>
       bookmark_manager_private_drag_event_router_;
 
   // The URL this WebUI was created for.
   GURL url_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_WEB_UI_H_