[WIP] Top-level await integration

The purpose of this patch is to nail down how HTML would
adjust to the needs of top-level await. The relevant change is,
the module.Evaluate() method will return a Promise that resolves
when the module is ready.

Top-level await should reach stage 3 before this change lands.

The PR where Evaluate returns a Promise is
guybedford/proposal-top-level-await#1

Author: littledan

source

@@ -3076,6 +3076,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isconstructor">IsConstructor</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isdatadescriptor">IsDataDescriptor</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-isdetachedbuffer">IsDetachedBuffer</dfn> abstract operation</li>
+     <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-ispromise">IsPromise</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-issharedarraybuffer">IsSharedArrayBuffer</dfn> abstract operation</li>
      <li>The <dfn data-x="js-NewObjectEnvironment" data-x-href="https://tc39.es/ecma262/#sec-newobjectenvironment">NewObjectEnvironment</dfn> abstract operation</li>
      <li>The <dfn data-x-href="https://tc39.es/ecma262/#sec-normalcompletion">NormalCompletion</dfn> abstract operation</li>
@@ -3131,6 +3132,9 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
     <p>User agents that support JavaScript must also implement the <cite>BigInt</cite> proposal. <ref
     spec=JSBIGINT></p>
 
+    <p>User agents that support JavaScript must also implement the <cite>top-level await</cite>
+    proposal: <ref spec=JSTLA></p>
+
    </dd>
 
 
@@ -89294,6 +89298,15 @@ interface <dfn>ApplicationCache</dfn> : <span>EventTarget</span> {
     </ol>
    </li>
 
+   <li>
+    <p>If <span>IsPromise</span>(<var>evaluationStatus</var>) is true, then:</p>
+
+    <ol>
+     <li><p>Upon rejection of <var>evaluationStatus</var> with <var>reason</var>,
+     <span>report the exception</span> given by <var>reason</var> for <var>script</var>.</p></li>
+    </ol>
+   </li>
+
    <li><p><span>Clean up after running script</span> with <var>settings</var>.</p></li>
 
    <li><p>Return <var>evaluationStatus</var>.</p></li>
@@ -90372,12 +90385,26 @@ import "https://example.com/foo/../module2.mjs";</code></pre>
    </li>
 
    <li><p><span data-x="run a module script">Run the module script</span> <var>result</var>, with
-   the rethrow errors boolean set to true.</p></li>
+   the rethrow errors boolean set to true, and let the result be <var>status</var>.</p></li>
 
    <li><p>If running the module script throws an exception, then perform
    <span>FinishDynamicImport</span>(<var>referencingScriptOrModule</var>, <var>specifier</var>,
    <var>promiseCapability</var>, the thrown exception completion).</p></li>
 
+   <li>
+    <p>If <span>IsPromise</span>(<var>status</var>) is true, then:</p>
+
+    <ol>
+     <li>Upon fulfillment of <var>status</var> with <var>value</var>, perform
+     <span>FinishDynamicImport</span>(<var>referencingScriptOrModule</var>, <var>specifier</var>,
+     <var>promiseCapability</var>, <var>value</var>).</li>
+
+     <li>Upon rejection of <var>status</var> with <var>reason</var>, perform
+     <span>FinishDynamicImport</span>(<var>referencingScriptOrModule</var>, <var>specifier</var>,
+     <var>promiseCapability</var>, Completion{ [[Type]]: throw, [[Value]]: <var>reason</var> }).</li>
+    </ol>
+   </li>
+
    <li><p>Otherwise, perform
    <span>FinishDynamicImport</span>(<var>referencingScriptOrModule</var>, <var>specifier</var>,
    <var>promiseCapability</var>, <span>NormalCompletion</span>(undefined)).</p></li>
@@ -123519,6 +123546,9 @@ INSERT INTERFACES HERE
    <dt id="refsJSINTL">[JSINTL]</dt>
    <dd><cite><a href="https://tc39.es/ecma402/">ECMAScript Internationalization API Specification</a></cite>. Ecma International.</dd>
 
+   <dt id="refsJSTLA">[JSTLA]</dt>
+   <dd><cite><a href="https://tc39.es/proposal-top-level-await/">Top Level Await</a></cite>. Ecma International.</dd>
+
    <dt id="refsJSON">[JSON]</dt>
    <dd><cite><a href="https://tools.ietf.org/html/rfc7159">The JavaScript Object Notation (JSON) Data Interchange Format</a></cite>, T. Bray. IETF.</dd>