Revert "make use of native IntersectionObserver in 3p iframe (ampproj…

…ect#6503)" (ampproject#6685)

This reverts commit 7ff2657.

3p/integration.js

@@ -130,15 +130,6 @@ import {zedo} from '../ads/zedo';
 import {zergnet} from '../ads/zergnet';
 import {zucks} from '../ads/zucks';
 
-/**
- * This value is copied here to avoid importing from src/intersection-observer-polyfill.js
- * Please keep this value same with DEFAULT_THRESHOLD from that file.
- * @const @private {!Array}
- */
-const DEFAULT_THRESHOLD =
-    [0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4,
-    0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1];
-
 /**
  * Whether the embed type may be used with amp-embed tag.
  * @const {!Object<string, boolean>}
@@ -439,16 +430,6 @@ function triggerRenderStart(opt_data) {
  */
 function observeIntersection(observerCallback) {
   // Send request to received records.
-  if (window.IntersectionObserver && window.IntersectionObserver.prototype) {
-    // use native IntersectionObserver if exist
-    const io = new window.IntersectionObserver(changes => {
-      observerCallback(changes);
-    }, {
-      threshold: DEFAULT_THRESHOLD,
-    });
-    io.observe(window.document.documentElement);
-    return () => io.unobserve(window.document.documentElement);
-  }
   nonSensitiveDataPostMessage('send-intersections');
   return listenParent(window, 'intersection', data => {
     observerCallback(data.changes);

ads/_ping_.js

@@ -22,11 +22,7 @@ import {dev} from '../src/log';
  */
 export function _ping_(global, data) {
   global.document.getElementById('c').textContent = data.ping;
-  if (!data.nativeIntersectionObserver) {
-    const nullIO = () => {};
-    nullIO.prototype = null;
-    global.IntersectionObserver = nullIO;
-  }
+
   if (data.ad_container) {
     dev().assert(
         global.context.container == data.ad_container, 'wrong container');
@@ -51,17 +47,12 @@ export function _ping_(global, data) {
     } else {
       global.context.renderStart();
     }
-    const unlisten = global.context.observeIntersection(function(changes) {
+    global.context.observeIntersection(function(changes) {
       changes.forEach(function(c) {
         dev().info('AMP-AD', 'Intersection: (WxH)' +
             `${c.intersectionRect.width}x${c.intersectionRect.height}`);
       });
     });
-    if (data.unlistenIo) {
-      global.setTimeout(() => {
-        unlisten();
-      }, Number(data.unlistenIo));
-    }
   } else {
     global.context.noContentAvailable();
   }

ads/ads.extern.js

@@ -228,8 +228,6 @@ geckoTag.placementReady;
 data.plc;
 data.sz;
 data.extra;
-// _ping_
-data.nativeIntersectionObserver
 var Fusion;
 Fusion.on;
 Fusion.on.warning;

extensions/amp-ad/0.1/amp-ad-3p-impl.js

@@ -36,11 +36,6 @@ import {AdDisplayState, AmpAdUIHandler} from './amp-ad-ui';
 /** @const {!string} Tag name for 3P AD implementation. */
 export const TAG_3P_IMPL = 'amp-ad-3p-impl';
 
-/**
- * NOTE: For testing purpose of 3p ad, please consider using ad type `_ping_`,
- * as it disables native IntersectionObserver and sends renderStart signal.
- */
-
 export class AmpAd3PImpl extends AMP.BaseElement {
 
   /**

test/manual/fakead3p.amp.html

@@ -36,7 +36,6 @@ <h2 id="fakead3p_0">fake3pAd send render-start w/ width & height</h2>
         data-id='0'
         data-url='https://lh3.googleusercontent.com/pSECrJ82R7-AqeBCOEPGPM9iG9OEIQ_QXcbubWIOdkY=w400-h300-no-n'
         data-valid='true'
-        data-native-intersection-observer='true'
         data-ad-width=50
         data-ad-height=50
     </amp-ad>
@@ -49,8 +48,6 @@ <h2 id="fakead3p_0">fake3pAd send render-start w/o width or height</h2>
         data-id='0'
         data-url='https://lh3.googleusercontent.com/pSECrJ82R7-AqeBCOEPGPM9iG9OEIQ_QXcbubWIOdkY=w400-h300-no-n'
         data-valid='true'
-        data-native-intersection-observer='true'
-        data-unlisten-io=1000
     </amp-ad>
   </div>