Remove TODOs to remove the "new back shortcut bubble".

chrome/app/chrome_command_ids.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_APP_CHROME_COMMAND_IDS_H_
 #define CHROME_APP_CHROME_COMMAND_IDS_H_
 
 // This file lists all the command IDs understood by e.g. the browser.
 // It is used by Windows RC files, Mac NIB files, and other platforms too.
 
@@ skipping 11 matching lines @@
 // TODO: Reorder to be in visible order; collapse holes
 #define IDC_BACK                        33000
 #define IDC_FORWARD                     33001
 #define IDC_RELOAD                      33002
 #define IDC_HOME                        33003
 #define IDC_OPEN_CURRENT_URL            33004
 #define IDC_STOP                        33006
 #define IDC_RELOAD_BYPASSING_CACHE      33007
 #define IDC_LOAD_NEW_TAB_PAGE           33008
 #define IDC_RELOAD_CLEARING_CACHE       33009
-// Temporary commands to capture the old Back/Forward shortcuts and tell users
-// the new shortcut. May also trigger Back/Forward action if the
-// BackspaceGoesBack field trial is enabled.
-// TODO(mgiuca): Remove these in M54 (https://crbug.com/610039).
 #define IDC_BACKSPACE_BACK              33010
 #define IDC_BACKSPACE_FORWARD           33011
 
 // Window management commands
 #define IDC_NEW_WINDOW                  34000
 #define IDC_NEW_INCOGNITO_WINDOW        34001
 #define IDC_PIN_TO_START_SCREEN         34005
 #define IDC_CLOSE_WINDOW                34012
 #define IDC_ALWAYS_ON_TOP               34013
 #define IDC_NEW_TAB                     34014
@@ skipping 306 matching lines @@
 // See http://msdn.microsoft.com/en-us/library/t2zechd4(VS.71).aspx
 
 // Starting command id for menus showing bookmarks (such as the wrench menu).
 // While command ids passed to Windows functions must not be higher than 0xDFFF,
 // these IDs are not exposed to the native system and thus can be in this
 // otherwise-reserved range. No command used in a menu (such as the wrench menu)
 // should be higher than this, otherwise it'll conflict.
 #define IDC_FIRST_BOOKMARK_MENU 0xE000
 
 #endif  // CHROME_APP_CHROME_COMMAND_IDS_H_