Enabled pressing TAB to cycle through the Omnibox results.

chrome/browser/autocomplete/autocomplete_popup_view_mac.mm

Index: chrome/browser/autocomplete/autocomplete_popup_view_mac.mm
===================================================================
--- chrome/browser/autocomplete/autocomplete_popup_view_mac.mm	(revision 81359)
+++ chrome/browser/autocomplete/autocomplete_popup_view_mac.mm	(working copy)
@@ -543,11 +543,13 @@
   // relevant strings out to make sure they stay alive until the call
   // completes.
   const AutocompleteMatch& match = model_->result().match_at(row);
+  string16 keyword;
+  if (match.has_keyword_hint())
+    keyword.assign(match.keyword);
+
   const GURL url(match.destination_url);
-  string16 keyword;
-  const bool is_keyword_hint = model_->GetKeywordForMatch(match, &keyword);
   edit_view_->OpenURL(url, disposition, match.transition, GURL(), row,
-                      is_keyword_hint ? string16() : keyword);
+                      keyword);
 }
 
 void AutocompletePopupViewMac::UserPressedOptIn(bool opt_in) {