Finally I find the extension I was dreaming to have. This extension is a must have for me and as firefox user I was using chrome ONLY because there was a similar extension that I could not find for firefox. You can easily customize the add-on and make your own search engines.
EX: add this in the addon settings: https://translate.google.com/?source=gtx_c#auto/en/{searchTerms} and now you can select any text and directly get a translation on google translate. I have added my favorite dictionaries like Larousse, Merriam-Webster etc.. and I have a translation with one click.
Million Thanks for the excellent job.