This extension is pretty sweet:
Type or paste a plain-text HTTP Request in a window and execute it with a click. Even runs CURL statements as well.
POST https://example.com/comments HTTP/1.1 Content-Type: application/xml Authorization: token xxx <request> <name>sample</name> <time>Wed, 21 Oct 2015 18:27:50 GMT</time> </request>
It certainly is no replacement for Postman or Graph Explorer, but sometimes you just need a quick call to visualize/validate the payload.