Call CreateDefaultOrdinals() when needed, instead of on construction

chrome/browser/extensions/extension_sorting.h

Index: chrome/browser/extensions/extension_sorting.h
diff --git a/chrome/browser/extensions/extension_sorting.h b/chrome/browser/extensions/extension_sorting.h
index d3fbe9069c36468e4175cdc841a370e77eb5f976..9c5ec799e8916d4c95e367464541b902b1e525c0 100644
--- a/chrome/browser/extensions/extension_sorting.h
+++ b/chrome/browser/extensions/extension_sorting.h
@@ -185,7 +185,7 @@ class ExtensionSorting {
   // 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|
@@ -213,6 +213,10 @@ class ExtensionSorting {
   // Defines the default ordinals.
   AppOrdinalsMap default_ordinals_;
 
+  // Used to construct the default ordinals once when needed instead of on
+  // construction when the app order may not have been determined.
+  bool default_ordinals_created_;
+
   // The set of extensions that don't appear in the new tab page.
   std::set<std::string> ntp_hidden_extensions_;