In most browsers the share button is openly displayed on the website you’re visiting. Either in the toolbar beside the back, forward and tab buttons like in safari. Or beside the address button like in chrome.
but in firefox, to share something to a friend or colleague, you have to go in to the browser menu to find the share button. I think it would be better to display that button openly, it doesn’t matter if you do it the safari way or the chrome way. Just display it so everyone can find it.