Fixed a bug with my recent PR: ampproject#5621.

hasOwn doesn't exist when the object is created using `map()`. Added a
test as well.

extensions/amp-analytics/0.1/amp-analytics.js

@@ -46,6 +46,8 @@ variableServiceFor(AMP.win);
 
 const MAX_REPLACES = 16; // The maximum number of entries in a extraUrlParamsReplaceMap
 
+const hasOwn = Object.prototype.hasOwnProperty;
+
 export class AmpAnalytics extends AMP.BaseElement {
 
   /** @param {!AmpElement} element */
@@ -570,7 +572,7 @@ export class AmpAnalytics extends AMP.BaseElement {
       user().assert(opt_predefinedConfig || property != 'iframePing',
           'iframePing config is only available to vendor config.');
       // Only deal with own properties.
-      if (from.hasOwnProperty(property)) {
+      if (hasOwn.call(from, property)) {
         if (isArray(from[property])) {
           if (!isArray(to[property])) {
             to[property] = [];

extensions/amp-analytics/0.1/test/test-amp-analytics.js

@@ -33,6 +33,7 @@ import {markElementScheduledForTesting} from '../../../../src/custom-element';
 import {installCidService,} from
     '../../../../extensions/amp-analytics/0.1/cid-impl';
 import {urlReplacementsForDoc} from '../../../../src/url-replacements';
+import {map} from '../../../../src/types';
 import * as sinon from 'sinon';
 
 import {AmpDocSingle} from '../../../../src/service/ampdoc-impl';
@@ -386,6 +387,8 @@ describe('amp-analytics', function() {
 
     return analytics.layoutCallback().then(() => {
       expect(analytics.mergeObjects_({}, {})).to.deep.equal({});
+      expect(analytics.mergeObjects_(map({'a': 0}), map({'b': 1})))
+          .to.deep.equal(map({'a': 0, 'b': 1}));
       expect(analytics.mergeObjects_({'foo': 1}, {'1': 1}))
           .to.deep.equal({'foo': 1, '1': 1});
       expect(analytics.mergeObjects_({'1': 1}, {'bar': 'bar'}))