ExtensionPrefs: remove FixMissingPrefs

extensions/browser/extension_prefs.h

Index: extensions/browser/extension_prefs.h
diff --git a/extensions/browser/extension_prefs.h b/extensions/browser/extension_prefs.h
index 96b590fe9ad8360249a8489ff9ed492a02c8c196..b20afc459a7a693bf35f5ccfc1f5f371da6a3fe6 100644
--- a/extensions/browser/extension_prefs.h
+++ b/extensions/browser/extension_prefs.h
@@ -622,10 +622,6 @@ class ExtensionPrefs : public ExtensionScopedPrefs, public KeyedService {
                             int reasons,
                             DisableReasonChange change);
 
-  // Fix missing preference entries in the extensions that are were introduced
-  // in a later Chrome version.
-  void FixMissingPrefs(const ExtensionIdList& extension_ids);
-
   // Installs the persistent extension preferences into |prefs_|'s extension
   // pref store. Does nothing if extensions_disabled_ is true.
   void InitPrefStore();