It seems to be a silly thing to remove from the UI from a usability point of view. There is no indication to the user of what this button does, or even that it's a button. For a new user coming to Chrome for the first time, how would they know to click the small unlabelled button to create a new tab? For me personally, I thought there had been an issue with the update. I searched to see if there was any information on a potentially known bug only to find this thread and learn that it was removed for aesthetics?!