Disable macro-after-long-task in inabox. (ampproject#26459)

src/chunk.js

@@ -30,6 +30,7 @@ const TAG = 'CHUNK';
  * @type {boolean}
  */
 let deactivated = /nochunking=1/.test(self.location.hash);
+let allowLongTasks = false;
 
 /**
  * @const {!Promise}
@@ -114,6 +115,14 @@ export function deactivateChunking() {
   deactivated = true;
 }
 
+/**
+ * Allow continuing macro tasks after a long task (>5ms).
+ * In particular this is the case when AMP runs in the `amp-inabox` ads mode.
+ */
+export function allowLongTasksInChunking() {
+  allowLongTasks = true;
+}
+
 /**
  * @visibleForTesting
  */
@@ -443,7 +452,11 @@ class Chunks {
     // If we've spent over 5 millseconds executing the
     // last instruction yeild back to the main thread.
     // 5 milliseconds is a magic number.
-    if (this.bodyIsVisible_ && this.durationOfLastExecution_ > 5) {
+    if (
+      !allowLongTasks &&
+      this.bodyIsVisible_ &&
+      this.durationOfLastExecution_ > 5
+    ) {
       this.durationOfLastExecution_ = 0;
       this.requestMacroTask_();
       return;

src/inabox/amp-inabox.js

@@ -22,6 +22,7 @@ import '../polyfills';
 import {Navigation} from '../service/navigation';
 import {Services} from '../services';
 import {adopt} from '../runtime';
+import {allowLongTasksInChunking, startupChunk} from '../chunk';
 import {cssText as ampSharedCss} from '../../build/ampshared.css';
 import {doNotTrackImpression} from '../impression';
 import {fontStylesheetTimeout} from '../font-stylesheet-timeout';
@@ -43,7 +44,6 @@ import {
 } from '../style-installer';
 import {internalRuntimeVersion} from '../internal-version';
 import {maybeValidate} from '../validator-integration';
-import {startupChunk} from '../chunk';
 import {stubElementsForDoc} from '../service/custom-element-registry';
 
 getMode(self).runtime = 'inabox';
@@ -69,6 +69,7 @@ try {
   makeBodyVisibleRecovery(self.document);
   throw e;
 }
+allowLongTasksInChunking();
 startupChunk(self.document, function initial() {
   /** @const {!../service/ampdoc-impl.AmpDoc} */
   const ampdoc = ampdocService.getAmpDoc(self.document);