Adds back BookmarkNode::IsVisible. Turns out we want to conditionally

chrome/browser/bookmarks/bookmark_model.h

Index: chrome/browser/bookmarks/bookmark_model.h
diff --git a/chrome/browser/bookmarks/bookmark_model.h b/chrome/browser/bookmarks/bookmark_model.h
index 4b242c2d837e867385b74c4ff951f1e6b93690fe..e6d7c8ffaa7c48dc1b9b6741f7b86b1cb5aa8abe 100644
--- a/chrome/browser/bookmarks/bookmark_model.h
+++ b/chrome/browser/bookmarks/bookmark_model.h
@@ -110,6 +110,13 @@ class BookmarkNode : public ui::TreeNode<BookmarkNode> {
     favicon_load_handle_ = handle;
   }
 
+  // Accessor method for controlling the visibility of a bookmark node/sub-tree.
+  // Note that visibility is not propagated down the tree hierarchy so if a
+  // parent node is marked as invisible, a child node may return "Visible". This
+  // function is primarily useful when traversing the model to generate a UI
+  // representation but we may want to suppress some nodes.
+  virtual bool IsVisible() const;
+
   // TODO(sky): Consider adding last visit time here, it'll greatly simplify
   // HistoryContentsProvider.