simplified overleaf routes and added dynamic cookie domain

app/coffee/infrastructure/Server.coffee

 Path = require "path"
 express = require('express')
 Settings = require('settings-sharelatex')
+
 logger = require 'logger-sharelatex'
 metrics = require('metrics-sharelatex')
 crawlerLogger = require('./CrawlerLogger')
@@ -78,23 +79,27 @@ app.use OldAssetProxy
 
 webRouter.use cookieParser(Settings.security.sessionSecret)
 
-webRouter.use (req, res, next)->
-	req.isOverleaf = req.headers.host.indexOf("overleaf") != -1
-	next()
-
-webRouter.use session
+sessionConfig = 
 	resave: false
 	saveUninitialized:false
 	secret:Settings.security.sessionSecret
 	proxy: Settings.behindProxy
 	cookie:
-		domain: if Settings.isOverleaf then Settings.overleaf.cookieDomain else Settings.cookieDomain
+		domain: Settings.cookieDomain
 		maxAge: Settings.cookieSessionLength
 		secure: Settings.secureCookie
 	store: sessionStore
 	key: Settings.cookieName
 	rolling: true
 
+webRouter.use (req, res, next)->
+	req.isOverleaf = req.headers.host.indexOf("overleaf") != -1
+	if req.isOverleaf
+		sessionConfig.cookie.domain = Settings.overleaf.cookieDomain
+		session(sessionConfig)(req, res, next)
+	else
+		session(sessionConfig)(req, res, next)
+
 # passport
 webRouter.use passport.initialize()
 webRouter.use passport.session()
@@ -148,14 +153,6 @@ webRouter.use (req, res, next) ->
 		res.status(503)
 		res.render("general/closed", {title:"maintenance"})
 
-onlyOnOverleaf = (req, res, next)->
-	if req.isOverleaf
-		next()
-	else
-		ErrorController.notFound(req, res)
-		
-webRouter.use(onlyOnOverleaf, require('../ol_router'));
-
 profiler = require "v8-profiler"
 privateApiRouter.get "/profile", (req, res) ->
 	time = parseInt(req.query.time || "1000")

app/coffee/ol_router.coffee

-ol_router = require('express').Router();
-
-ol_router.use '/is_ol', (req, res)->
-	res.send("true")
-
-module.exports = ol_router
\ No newline at end of file

app/coffee/router.coffee

@@ -48,11 +48,19 @@ LabelsController = require('./Features/Labels/LabelsController')
 logger = require("logger-sharelatex")
 _ = require("underscore")
 
+onlyOnOverleaf = (req, res, next)->
+	if req.isOverleaf
+		next()
+	else
+		ErrorController.notFound(req, res)
+
 module.exports = class Router
 	constructor: (webRouter, privateApiRouter, publicApiRouter)->
 		if !Settings.allowPublicAccess
 			webRouter.all '*', AuthenticationController.requireGlobalLogin
 
+		webRouter.get '/is_ol', onlyOnOverleaf, (req, res)->
+			res.send("true")
 
 		webRouter.get  '/login', UserPagesController.loginPage
 		AuthenticationController.addEndpointToLoginWhitelist '/login'