[Mac] Don't handle up/down-arrow unless popup is visible.

chrome/browser/autocomplete/autocomplete_edit_view_mac.h

Index: chrome/browser/autocomplete/autocomplete_edit_view_mac.h
diff --git a/chrome/browser/autocomplete/autocomplete_edit_view_mac.h b/chrome/browser/autocomplete/autocomplete_edit_view_mac.h
index e564706e0e6487f605ff9833824be18754e91183..854099b9be7d1211ab6d48574abb8e20cd9d4da1 100644
--- a/chrome/browser/autocomplete/autocomplete_edit_view_mac.h
+++ b/chrome/browser/autocomplete/autocomplete_edit_view_mac.h
@@ -87,6 +87,9 @@ class AutocompleteEditViewMac : public AutocompleteEditView {
   // Helper functions for use from AutocompleteEditHelper Objective-C
   // class.
 
+  // Returns true if |popup_view_| is open.
+  bool IsPopupOpen() const;
+
   // Trivial wrappers forwarding to |model_| methods.
   void OnControlKeyChanged(bool pressed);
   void OnEscapeKeyPressed();