Remove unneeded utilGetPrototypeOf and just use Object.getPrototypeOf

modules/core/graph.js

@@ -2,7 +2,6 @@ import _difference from 'lodash-es/difference';
 import _includes from 'lodash-es/includes';
 
 import { debug } from '../index';
-import { utilGetPrototypeOf } from '../util';
 
 
 export function coreGraph(other, mutable) {
@@ -125,9 +124,9 @@ coreGraph.prototype = {
 
     base: function() {
         return {
-            'entities': utilGetPrototypeOf(this.entities),
-            'parentWays': utilGetPrototypeOf(this._parentWays),
-            'parentRels': utilGetPrototypeOf(this._parentRels)
+            'entities': Object.getPrototypeOf(this.entities),
+            'parentWays': Object.getPrototypeOf(this._parentWays),
+            'parentRels': Object.getPrototypeOf(this._parentRels)
         };
     },
 

modules/util/index.js

@@ -13,7 +13,6 @@ export { utilEntityOrDeepMemberSelector } from './util';
 export { utilFastMouse } from './util';
 export { utilFunctor } from './util';
 export { utilGetAllNodes } from './util';
-export { utilGetPrototypeOf } from './util';
 export { utilGetSetValue } from './get_set_value';
 export { utilHashcode } from './util';
 export { utilHighlightEntities } from './util';

modules/util/util.js

@@ -283,11 +283,6 @@ export function utilFastMouse(container) {
 }
 
 
-/* eslint-disable no-proto */
-export var utilGetPrototypeOf = Object.getPrototypeOf || function(obj) { return obj.__proto__; };
-/* eslint-enable no-proto */
-
-
 export function utilAsyncMap(inputs, func, callback) {
     var remaining = inputs.length;
     var results = [];

test/spec/util/util.js

@@ -71,13 +71,6 @@ describe('iD.util', function() {
         expect(iD.utilQsString({})).to.eql('');
     });
 
-    it('utilGetPrototypeOf', function() {
-        var a = function() {};
-        a.prototype = { foo: 'foo' };
-        expect(iD.utilGetPrototypeOf({})).to.eql({});
-        expect(iD.utilGetPrototypeOf(new a())).to.eql({ foo: 'foo' });
-    });
-
     describe('utilEditDistance', function() {
         it('returns zero for same strings', function() {
             expect(iD.utilEditDistance('foo', 'foo')).to.eql(0);