Add the feature "Add as seach engine..." when right clicking on ...

chrome/app/chrome_command_ids.h

 // 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.
 
 #ifndef CHROME_APP_CHROME_COMMAND_IDS_H_
 #define CHROME_APP_CHROME_COMMAND_IDS_H_
 #pragma once
 
 // 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 250 matching lines @@
 #define IDC_CONTENT_CONTEXT_LANGUAGE_SETTINGS 50153
 #define IDC_CONTENT_CONTEXT_LOOK_UP_IN_DICTIONARY 50154
 #define IDC_CONTENT_CONTEXT_NO_SPELLING_SUGGESTIONS 50155
 // Frame items.
 #define IDC_CONTENT_CONTEXT_RELOADFRAME 50160
 #define IDC_CONTENT_CONTEXT_VIEWFRAMESOURCE 50161
 #define IDC_CONTENT_CONTEXT_VIEWFRAMEINFO 50162
 // Search items.
 #define IDC_CONTENT_CONTEXT_GOTOURL 50170
 #define IDC_CONTENT_CONTEXT_SEARCHWEBFOR 50171
+#define IDC_CONTENT_CONTEXT_ADDSEARCHENGINE 50172
 
 // Context menu items in the bookmark bar
 #define IDC_BOOKMARK_BAR_OPEN_ALL 51000
 #define IDC_BOOKMARK_BAR_OPEN_ALL_NEW_WINDOW 51001
 #define IDC_BOOKMARK_BAR_OPEN_ALL_INCOGNITO 51002
 #define IDC_BOOKMARK_BAR_OPEN_INCOGNITO 51003
 #define IDC_BOOKMARK_BAR_RENAME_FOLDER 51004
 #define IDC_BOOKMARK_BAR_EDIT 51005
 #define IDC_BOOKMARK_BAR_REMOVE 51006
 #define IDC_BOOKMARK_BAR_ADD_NEW_BOOKMARK 51007
 #define IDC_BOOKMARK_BAR_NEW_FOLDER 51008
 #define IDC_BOOKMARK_MANAGER 51009
 #define IDC_BOOKMARK_BAR_ALWAYS_SHOW 51010
 
 // Context menu items in the status tray
 #define IDC_STATUS_TRAY_KEEP_CHROME_RUNNING_IN_BACKGROUND 51100
 
 // Protocol handler menu entries
 #define IDC_CONTENT_CONTEXT_PROTOCOL_HANDLER_FIRST     52000
 #define IDC_CONTENT_CONTEXT_PROTOCOL_HANDLER_LAST      52199
 #define IDC_CONTENT_CONTEXT_PROTOCOL_HANDLER_SETTINGS  52200
 
 // NOTE: The last valid command value is 57343 (0xDFFF)
 // See http://msdn.microsoft.com/en-us/library/t2zechd4(VS.71).aspx
 
 #endif  // CHROME_APP_CHROME_COMMAND_IDS_H_