Documented that the new nodes at the root aren't meant to sync.

chrome/browser/sync/glue/bookmark_change_processor.cc

Index: chrome/browser/sync/glue/bookmark_change_processor.cc
diff --git a/chrome/browser/sync/glue/bookmark_change_processor.cc b/chrome/browser/sync/glue/bookmark_change_processor.cc
index 67cce64e5616704c83bf5f4994e42246cf8dd680..14d8cd4a74969c31479f86ba60fe33981b91f9da 100644
--- a/chrome/browser/sync/glue/bookmark_change_processor.cc
+++ b/chrome/browser/sync/glue/bookmark_change_processor.cc
@@ -149,6 +149,8 @@ void BookmarkChangeProcessor::RemoveAllSyncNodes() {
             syncer::kInvalidId) {
       RemoveAllChildNodes(&trans, bookmark_model_->mobile_node()->id());
     }
+    // Note: the root node may have additional extra nodes. Currently none of
+    // them are meant to sync.
   }
 
   // Don't need to update versions of deleted nodes.