Call CreateDefaultOrdinals() when needed, instead of on construction

chrome/browser/extensions/extension_sorting.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_SORTING_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SORTING_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 167 matching lines @@
   void SyncIfNeeded(const std::string& extension_id);
 
   // Creates the default ordinals.
   void CreateDefaultOrdinals();
 
   // Gets the default ordinals for |extension_id|. Returns false if no default
   // ordinals for |extension_id| is defined. Otherwise, returns true and
   // ordinals is updated with corresponding ordinals.
   bool GetDefaultOrdinals(const std::string& extension_id,
                           syncer::StringOrdinal* page_ordinal,
-                          syncer::StringOrdinal* app_launch_ordinal) const;
+                          syncer::StringOrdinal* app_launch_ordinal);
 
   // Returns |app_launch_ordinal| if it has no collision in the page specified
   // by |page_ordinal|. Otherwise, returns an ordinal after |app_launch_ordinal|
   // that has no conflict.
   syncer::StringOrdinal ResolveCollision(
       const syncer::StringOrdinal& page_ordinal,
       const syncer::StringOrdinal& app_launch_ordinal) const;
 
   // Returns the number of items in |m| visible on the new tab page.
   size_t CountItemsVisibleOnNtp(const AppLaunchOrdinalMap& m) const;
@@ skipping 14 matching lines @@
   // Defines the default ordinals.
   AppOrdinalsMap default_ordinals_;
 
   // The set of extensions that don't appear in the new tab page.
   std::set<std::string> ntp_hidden_extensions_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSorting);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SORTING_H_