GetNull            36 content/renderer/accessibility/blink_ax_tree_source.h   virtual blink::WebAXObject GetNull() const OVERRIDE;
GetNull           194 ui/accessibility/ax_tree_serializer.h     return tree_->GetNull();
GetNull           211 ui/accessibility/ax_tree_serializer.h   AXSourceNode lca = tree_->GetNull();
GetNull           255 ui/accessibility/ax_tree_serializer.h         *out_lca = tree_->GetNull();
GetNull            53 ui/accessibility/ax_tree_source.h   virtual AXNodeSource GetNull() const = 0;