Remove unneeded [].indexOf fallback

atom/browser/api/lib/dialog.js

@@ -4,7 +4,7 @@ const binding = process.atomBinding('dialog');
 const v8Util = process.atomBinding('v8_util');
 
 var slice = [].slice;
-var indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
+var indexOf = [].indexOf;
 
 var fileDialogProperties = {
   openFile: 1 << 0,

atom/renderer/api/lib/desktop-capturer.js

@@ -2,7 +2,7 @@ const ipcRenderer = require('electron').ipcRenderer;
 const nativeImage = require('electron').nativeImage;
 
 var nextId = 0;
-var indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
+var indexOf = [].indexOf;
 
 var getNextId = function() {
   return ++nextId;

atom/renderer/api/lib/remote.js

@@ -4,7 +4,7 @@ const v8Util = process.atomBinding('v8_util');
 
 const callbacksRegistry = new CallbacksRegistry;
 
-var indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
+var indexOf = [].indexOf;
 
 // Check for circular reference.
 var isCircular = function(field, visited) {