Enabled pressing TAB to cycle through the Omnibox results.

chrome/browser/ui/gtk/omnibox/omnibox_view_gtk.h

Index: chrome/browser/ui/gtk/omnibox/omnibox_view_gtk.h
===================================================================
--- chrome/browser/ui/gtk/omnibox/omnibox_view_gtk.h	(revision 119905)
+++ chrome/browser/ui/gtk/omnibox/omnibox_view_gtk.h	(working copy)
@@ -106,7 +106,9 @@
                            const string16& display_text,
                            bool update_popup) OVERRIDE;
   virtual void SetWindowTextAndCaretPos(const string16& text,
-                                        size_t caret_pos) OVERRIDE;
+                                        size_t caret_pos,
+                                        bool update_popup,
+                                        bool notify_text_changed) OVERRIDE;
   virtual void SetForcedQuery() OVERRIDE;
   virtual bool IsSelectAll() OVERRIDE;
   virtual bool DeleteAtEndPressed() OVERRIDE;
@@ -461,6 +463,11 @@
   // during sync dispatch of "move-focus" signal.
   bool tab_was_pressed_;
 
+  // Indicates if Shift key was pressed.
+  // Used in conjunction with the Tab key to determine if either traversal
+  // needs to move up the results or if the keyword needs to be cleared.
+  bool shift_was_pressed_;
+
   // Indicates that user requested to paste clipboard.
   // The actual paste clipboard action might be performed later if the
   // clipboard is not empty.