Enabled pressing TAB to cycle through the Omnibox results.

chrome/browser/ui/views/omnibox/omnibox_view_win.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/ui/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
@@ skipping 2034 matching lines @@
       }
 
       // We're showing a keyword and the user pressed backspace at the beginning
       // of the text. Delete the selected keyword.
       ScopedFreeze freeze(this, GetTextObjectModel());
       model_->ClearKeyword(GetText());
       return true;
     }
 
     case VK_TAB: {
-      if (model_->is_keyword_hint()) {
+      const bool shift_pressed = GetKeyState(VK_SHIFT) < 0;
+      if (model_->is_keyword_hint() && !shift_pressed) {
         // Accept the keyword.
         ScopedFreeze freeze(this, GetTextObjectModel());
         model_->AcceptKeyword();
-      } else if (!IsCaretAtEnd()) {
-        ScopedFreeze freeze(this, GetTextObjectModel());
-        OnBeforePossibleChange();
-        PlaceCaretAt(GetTextLength());
-        OnAfterPossibleChange();
+      } else if (shift_pressed &&
+                 model_->popup_model()->selected_line_state() ==
+                    AutocompletePopupModel::KEYWORD) {
+        model_->ClearKeyword(GetText());
       } else {
-        model_->CommitSuggestedText(true);
+        model_->OnUpOrDownKeyPressed(shift_pressed ? -count : count);
       }
       return true;
     }
 
     case 0xbb:  // Ctrl-'='.  Triggers subscripting (even in plain text mode).
                 // We don't use VK_OEM_PLUS in case the macro isn't defined.
                 // (e.g., we don't have this symbol in embeded environment).
       return true;
 
     default:
@@ skipping 576 matching lines @@
   // PosFromChar(i) might return 0 when i is greater than 1.
   return font_.GetStringWidth(text) + GetHorizontalMargin();
 }
 
 bool OmniboxViewWin::IsCaretAtEnd() const {
   long length = GetTextLength();
   CHARRANGE sel;
   GetSelection(sel);
   return sel.cpMin == sel.cpMax && sel.cpMin == length;
 }