tabContextHistoryMenu.uc.js
修正前後でエラーメッセージが変わった

nsFaviconService::GetFaviconForPage is deprecated and will be removed in the next version.
↓
nsFaviconService::GetFaviconImageForPage is deprecated and will be removed in the next version.

確認環境
Firefox21.0
user_pref("browser.chrome.favicons", false);
user_pref("browser.chrome.site_icons", false);