Support cntrl-tab to switch tabs on OS X.

chrome/browser/global_keyboard_shortcuts_mac.mm

 // Copyright (c) 2009 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/global_keyboard_shortcuts_mac.h"
 
 #include "base/basictypes.h"
 #include "chrome/app/chrome_dll_resource.h"
 
 const KeyboardShortcutData* GetKeyboardShortCutTable(size_t* num_entries) {
   static const KeyboardShortcutData keyboard_shortcuts[] = {
     {true,  true,  false, 30  /* ] */,       IDC_SELECT_NEXT_TAB},
     {false, false, true,  121 /* pg down */, IDC_SELECT_NEXT_TAB},
+    {false, false, true,  48 /* tab */,      IDC_SELECT_NEXT_TAB},
     {true,  true,  false, 33  /* [ */,       IDC_SELECT_PREVIOUS_TAB},
     {false, false, true,  116 /* pg_up */,   IDC_SELECT_PREVIOUS_TAB},
+    {false, true,  true,  48 /* tab */,      IDC_SELECT_PREVIOUS_TAB},
   };
 
   *num_entries = arraysize(keyboard_shortcuts);
 
   return keyboard_shortcuts;
 }
 
 int CommandForKeyboardShortcut(bool command_key, bool shift_key, bool cntrl_key,
     int vkey_code) {
 
   // Scan through keycodes and see if it corresponds to one of the global
   // shortcuts on file.
   //
   // TODO(jeremy): Change this into a hash table once we get enough
   // entries in the array to make a difference.
   size_t num_shortcuts = 0;
   const KeyboardShortcutData *it = GetKeyboardShortCutTable(&num_shortcuts);
   for (size_t i = 0; i < num_shortcuts; ++i, ++it) {
     if (it->command_key == command_key &&
         it->shift_key == shift_key &&
         it->cntrl_key == cntrl_key &&
         it->vkey_code == vkey_code) {
       return it->chrome_command;
     }
   }
 
   return -1;
 }