Move session-created event to app

This follows the convention of other *-created events.

lib/browser/api/session.js

@@ -1,13 +1,12 @@
 const {EventEmitter} = require('events')
-const electron = require('electron')
+const {app} = require('electron')
 const bindings = process.atomBinding('session')
 
 const PERSIST_PREFIX = 'persist:'
-const Session = new EventEmitter()
 
 // Wrapper of binding.fromPartition that checks for ready event.
 const fromPartition = function (partition, persist) {
-  if (!electron.app.isReady()) {
+  if (!app.isReady()) {
     throw new Error('session module can only be used when app is ready')
   }
 
@@ -15,7 +14,7 @@ const fromPartition = function (partition, persist) {
 }
 
 // Returns the Session from |partition| string.
-Session.fromPartition = function (partition = '') {
+exports.fromPartition = function (partition = '') {
   if (partition === '') return exports.defaultSession
 
   if (partition.startsWith(PERSIST_PREFIX)) {
@@ -26,7 +25,7 @@ Session.fromPartition = function (partition = '') {
 }
 
 // Returns the default session.
-Object.defineProperty(Session, 'defaultSession', {
+Object.defineProperty(exports, 'defaultSession', {
   enumerable: true,
   get: function () {
     return fromPartition('', false)
@@ -36,9 +35,7 @@ Object.defineProperty(Session, 'defaultSession', {
 const wrapSession = function (session) {
   // Session is an EventEmitter.
   Object.setPrototypeOf(session, EventEmitter.prototype)
-  Session.emit('session-created', session)
+  app.emit('session-created', session)
 }
 
 bindings._setWrapSession(wrapSession)
-
-module.exports = Session

lib/browser/chrome-extension.js

@@ -1,4 +1,4 @@
-const {app, ipcMain, session, webContents, BrowserWindow} = require('electron')
+const {app, ipcMain, webContents, BrowserWindow} = require('electron')
 const {getAllWebContents} = process.atomBinding('web_contents')
 const renderProcessPreferences = process.atomBinding('render_process_preferences').forAllWebContents()
 
@@ -333,7 +333,7 @@ app.once('ready', function () {
       }
     })
   }
-  session.on('session-created', function (ses) {
+  app.on('session-created', function (ses) {
     ses.protocol.registerBufferProtocol('chrome-extension', chromeExtensionHandler, function (error) {
       if (error) {
         console.error(`Unable to register chrome-extension protocol: ${error}`)