hipchat: Add HipChat API endpoints

The endpoints are documented here:
https://developer.atlassian.com/hipchat/guide/hipchat-rest-api/api-access-tokens

Change-Id: I4578f5683aa9ed728e503cb3b08ff0bf743a62a1
Reviewed-on: https://go-review.googlesource.com/21051
Reviewed-by: Burcu Dogan <[email protected]>

Author: SamWhited

hipchat/hipchat.go

@@ -0,0 +1,16 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package hipchat provides constants for using OAuth2 to access HipChat.
+package hipchat // import "golang.org/x/oauth2/hipchat"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is HipChat's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.hipchat.com/users/authorize",
+	TokenURL: "https://api.hipchat.com/v2/oauth/token",
+}