Enable sync for the settings from the Extension Settings API.

chrome/browser/sync/profile_sync_factory.h

Index: chrome/browser/sync/profile_sync_factory.h
diff --git a/chrome/browser/sync/profile_sync_factory.h b/chrome/browser/sync/profile_sync_factory.h
index 3c6156c13ee1a8bba1da6f7b2199ef0fe9f6638c..4a983686a75a1f402749ffa166a181c76865b2ff 100644
--- a/chrome/browser/sync/profile_sync_factory.h
+++ b/chrome/browser/sync/profile_sync_factory.h
@@ -96,6 +96,13 @@ class ProfileSyncFactory {
       browser_sync::UnrecoverableErrorHandler* error_handler) = 0;
 
   // Instantiates both a model associator and change processor for the
+  // extension setting data type.  The pointers in the return struct are
+  // owned by the caller.
+  virtual SyncComponents CreateExtensionSettingSyncComponents(
+      ProfileSyncService* profile_sync_service,
+      browser_sync::UnrecoverableErrorHandler* error_handler) = 0;
+
+  // Instantiates both a model associator and change processor for the
   // extension data type.  The pointers in the return struct are
   // owned by the caller.
   virtual SyncComponents CreateExtensionSyncComponents(