Enabled pressing TAB to cycle through the Omnibox results.

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

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_GTK_OMNIBOX_OMNIBOX_VIEW_GTK_H_
 #define CHROME_BROWSER_UI_GTK_OMNIBOX_OMNIBOX_VIEW_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
@@ skipping 88 matching lines @@
                          size_t index,
                          const string16& keyword) OVERRIDE;
   virtual string16 GetText() const OVERRIDE;
   virtual bool IsEditingOrEmpty() const OVERRIDE;
   virtual int GetIcon() const OVERRIDE;
   virtual void SetUserText(const string16& text) OVERRIDE;
   virtual void SetUserText(const string16& text,
                            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;
   virtual void GetSelectionBounds(string16::size_type* start,
                                   string16::size_type* end) const OVERRIDE;
   virtual void SelectAll(bool reversed) OVERRIDE;
   virtual void RevertAll() OVERRIDE;
   virtual void UpdatePopup() OVERRIDE;
   virtual void ClosePopup() OVERRIDE;
   virtual void SetFocus() OVERRIDE;
@@ skipping 400 matching lines @@
   // The view that is going to be focused next. Only valid while handling
   // "focus-out" events.
   GtkWidget* going_to_focus_;
 
   ui::GtkSignalRegistrar signals_;
 
   DISALLOW_COPY_AND_ASSIGN(OmniboxViewGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_OMNIBOX_OMNIBOX_VIEW_GTK_H_