Separate the syncing of extension settings and app settings into separate data

chrome/browser/extensions/extension_data_deleter.h

Index: chrome/browser/extensions/extension_data_deleter.h
diff --git a/chrome/browser/extensions/extension_data_deleter.h b/chrome/browser/extensions/extension_data_deleter.h
index 546c0d0b9e135f7e3a9c6c6a2e733955351e7913..a08090a9079d162da70c39982daf4e84e9d7b5d6 100644
--- a/chrome/browser/extensions/extension_data_deleter.h
+++ b/chrome/browser/extensions/extension_data_deleter.h
@@ -25,7 +25,6 @@ class URLRequestContextGetter;
 }
 
 class ChromeAppCacheService;
-class ExtensionSettingsBackend;
 class Profile;
 class WebKitContext;
 
@@ -81,10 +80,6 @@ class ExtensionDataDeleter
   // thread.
   void DeleteAppcachesOnIOThread();
 
-  // Deletes extension settings for the extension. Will be called on the FILE
-  // thread via the ExtensionSettingsFrontend.
-  void DeleteExtensionSettingsOnFileThread(ExtensionSettingsBackend* backend);
-
   // The ID of the extension being deleted.
   const std::string extension_id_;