--- a/services/sync/modules/collection_validator.js
+++ b/services/sync/modules/collection_validator.js
@@ -60,17 +60,17 @@ class CollectionValidator {
   }
 
   // Should a custom ProblemData type be needed, return it here.
   emptyProblemData() {
     return new CollectionProblemData();
   }
 
   getServerItems(engine) {
-    let collection = engine._itemSource();
+    let collection = engine.itemSource();
     let collectionKey = engine.service.collectionKeys.keyForCollection(engine.name);
     collection.full = true;
     let items = [];
     collection.recordHandler = function(item) {
       item.decrypt(collectionKey);
       items.push(item.cleartext);
     };
     collection.get();

--- a/services/sync/tps/extensions/tps/resource/tps.jsm
+++ b/services/sync/tps/extensions/tps/resource/tps.jsm
@@ -599,17 +599,17 @@ var TPS = {
 
   /**
    * Use Sync's bookmark validation code to see if we've corrupted the tree.
    */
   ValidateBookmarks() {
 
     let getServerBookmarkState = () => {
       let bookmarkEngine = Weave.Service.engineManager.get('bookmarks');
-      let collection = bookmarkEngine._itemSource();
+      let collection = bookmarkEngine.itemSource();
       let collectionKey = bookmarkEngine.service.collectionKeys.keyForCollection(bookmarkEngine.name);
       collection.full = true;
       let items = [];
       collection.recordHandler = function(item) {
         item.decrypt(collectionKey);
         items.push(item.cleartext);
       };
       collection.get();