DOES GMAIL WANT TO BE INSTANT MESSAGING? NEW UI EXPERIMENT SAYS “YES”

Summary from the TLDR Design newsletter

Android Police spotted a new UI experiment with a one-line input bar below a quick reply box that looks like instant messaging input. Above it, you can still select from the "reply," "reply all," or "forward" options. Also, you get an attachment and send controls and an "expand" button that seems to open the usual compose interface.