Integrate with the ES job queue

This integrates with the ES job queue for promise jobs, by overriding ES's EnqueueJob and NextJob to delegate to the microtask queue. This finally gives us a normative specification for how promises interface with the browser event loop.

This approach of monkeypatching ES is necessary for now. See discussions in tc39/ecma262#240 (comment) about how this is the least-bad alternative. We hope to update ES to delegate to the host for those operations in the future, instead of overwriting ES. That possibility is discussed in replies to the linked comment.

Also fixes a few uses of "ECMAScript"; this specification prefers "JavaScript".

This completes https://www.w3.org/Bugs/Public/show_bug.cgi?id=25981.

source

@@ -2938,7 +2938,7 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
     data-x="willful violation">despite it being an officially obsoleted type</span> according to RFC
     4329. <ref spec=RFC4329></p>
 
-    <p>The following terms are defined in the ECMAScript specification and used in this specification:</p>
+    <p>The following terms are defined in the JavaScript specification and used in this specification:</p>
 
     <ul class="brief">
 
@@ -2951,6 +2951,7 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
      <li><dfn data-noexport="" data-x-href="https://tc39.github.io/ecma262/#use-strict-directive">Use Strict Directive</dfn>
      <li>The <dfn data-noexport="" data-x="js-prod-Pattern" data-x-href="https://tc39.github.io/ecma262/#prod-Pattern"><i>Pattern</i></dfn> production</li>
      <li>The <dfn data-noexport="" data-x="js-prod-FunctionBody" data-x-href="https://tc39.github.io/ecma262/#prod-FunctionBody"><i>FunctionBody</i></dfn> production</li>
+     <li>The <dfn data-noexport="" data-x="js-EnqueueJob" data-x-href="https://tc39.github.io/ecma262/#sec-enqueuejob">EnqueueJob</dfn> abstract operation</li>
      <li>The <dfn data-noexport="" data-x="js-FunctionCreate" data-x-href="https://tc39.github.io/ecma262/#sec-functioncreate">FunctionCreate</dfn> abstract operation</li>
      <li>The <dfn data-noexport="" data-x="js-GetActiveScriptOrModule" data-x-href="https://tc39.github.io/ecma262/#sec-getactivescriptormodule">GetActiveScriptOrModule</dfn> abstract operation</li>
      <li>The <dfn data-noexport="" data-x="js-HostPromiseRejectionTracker" data-x-href="https://tc39.github.io/ecma262/#sec-host-promise-rejection-tracker">HostPromiseRejectionTracker</dfn> abstract operation</li>
@@ -2959,6 +2960,7 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
      <li>The <dfn data-noexport="" data-x="js-ParseScript" data-x-href="https://tc39.github.io/ecma262/#sec-parse-script">ParseScript</dfn> abstract operation</li>
      <li>The <dfn data-noexport="" data-x="js-ScriptEvaluation" data-x-href="https://tc39.github.io/ecma262/#sec-runtime-semantics-scriptevaluation">ScriptEvaluation</dfn> abstract operation</li>
      <li>The <dfn data-noexport="" data-x="js-ToBoolean" data-x-href="https://tc39.github.io/ecma262/#sec-toboolean">ToBoolean</dfn> abstract operation</li>
+     <li>The <dfn data-noexport="" data-x="js-NextJob" data-x-href="https://tc39.github.io/ecma262/#sec-nextjob-result">NextJob</dfn> algorithm step
      <li>The <dfn data-noexport="" data-x="js-abstract-equality" data-x-href="https://tc39.github.io/ecma262/#sec-abstract-equality-comparison">Abstract Equality Comparison</dfn> algorithm
      <li>The <dfn data-noexport="" data-x="js-strict-equality" data-x-href="https://tc39.github.io/ecma262/#sec-strict-equality-comparison">Strict Equality Comparison</dfn> algorithm
      <li>The <dfn data-noexport="" data-x-href="https://tc39.github.io/ecma262/#sec-date-objects"><code>Date</code></dfn> class
@@ -61668,7 +61670,7 @@ interface <dfn>Path2D</dfn> {
    <li><p>Let <var>input</var> be the argument to coerce.</p></li>
 
    <li><p>Let <var>jsval</var> be the result of <span data-x="concept-idl-convert">converting</span>
-   <var>input</var> to an ECMAScript value. If this throws an exception, then propagate the
+   <var>input</var> to a JavaScript value. If this throws an exception, then propagate the
    exception and abort these steps.</p></li>
 
    <li><p>Let <var>dict</var> be the result of <span data-x="concept-idl-convert">converting</span>
@@ -85954,6 +85956,65 @@ interface <dfn>NavigatorOnLine</dfn> {
   user with a mechanism to just close the page entirely, without running any <code
   data-x="event-unload">unload</code> event handlers.</p>
 
+  <h5>Integration with the JavaScript job queue</h5>
+
+  <p>The JavaScript specification defines the JavaScript job and job queue abstractions in order to
+  specify certain invariants about how promise operations execute with a clean <span>JavaScript
+  execution context stack</span> and in a certain order. However, as of the time of this writing
+  the definitions of <span data-x="js-NextJob">EnqueueJob</span> and <span
+  data-x="js-NextJob">NextJob</span> in that specification are not sufficiently flexible to
+  integrate with HTML as a host environment. <ref spec="ECMA262"></p>
+
+  <p class="note">This is not strictly true. It is in fact possible, by taking liberal advantage of
+  the many "implementation defined" sections of those algorithms, to contort them to our purposes.
+  However, the end result is a mass of messy indirection and workarounds that essentially bypasses
+  the job queue infrastructure entirely, albeit in a way that is technically sanctioned within the
+  bounds of implementation-defined behavior. We do not take this path, and instead introduce the
+  following <span data-x="willful violation">willful violations</span>.</p>
+
+  <p>As such, user agents must instead use the following definitions in place of those in the
+  JavaScript specification. These ensure that the promise jobs enqueued by the JavaScript
+  specification are properly integrated into the user agent's <span data-x="event loop">event
+  loops</span>.</p>
+
+  <h6><dfn>EnqueueJob</dfn>(<var>queueName</var>, <var>job</var>, <var>arguments</var>)</h6>
+
+  <p>When the JavaScript specification says to call the EnqueueJob abstract operation, the
+  following algorithm must be used in place of JavaScript's <span
+  data-x="js-EnqueueJob">EnqueueJob</span>:</p>
+
+  <ol>
+   <li><p>Assert: <var>queueName</var> is <code data-x="">"PromiseJobs"</code>. (<code
+   data-x="">"ScriptJobs"</code> must not be used by user agents.)</p></li>
+   <li><p>Let <var>settings</var> be the <span>settings object</span> of <span>the script
+   corresponding to the running execution context</span>.</p></li>
+   <li>
+    <p><span>Queue a microtask</span>, on <var>settings</var>'s <span>responsible event
+    loop</span>, to perform the following steps:</p>
+
+    <ol>
+     <li><p><span>Prepare to run a callback</span> with <var>settings</var>. If this returns "do
+     not run" then abort these steps.</p></li>
+     <li><p>Performing the abstract operation specified by <var>job</var>, using the elements of
+     <var>arguments</var> as its arguments.</p></li>
+     <li><p><span>Clean up after running a callback</span> with <var>settings</var>.</p></li>
+    </ol>
+   </li>
+  </ol>
+
+  <h6><dfn>NextJob</dfn> <var>result</var></h6>
+
+  <p>When the JavaScript specification uses the algorithm step NextJob, the following steps must be
+  used in place of those specified by JavaScript's <span data-x="js-NextJob">NextJob</span>:</p>
+
+  <ol>
+   <li><p>If <var>result</var> is an abrupt completion, <span>report the exception</span> given by
+   <var>result</var>.[[value]].</p></li>
+  </ol>
+
+  <p class="note">A more accurate name for our overridden version of NextJob would be along the
+  lines of "yield to host environment" or "allow host environment to react to job results".</p>
+
   </div>
 
 
@@ -86167,7 +86228,7 @@ dictionary <dfn>ErrorEventInit</dfn> : <span>EventInit</span> {
 
   <h6>The HostPromiseRejectionTracker implementation</h6>
 
-  <p>ECMAScript contains an implementation-defined <span
+  <p>JavaScript contains an implementation-defined <span
   data-x="js-HostPromiseRejectionTracker">HostPromiseRejectionTracker</span>(<var>promise</var>,
   <var>operation</var>) abstract operation. User agents must use the following implementation:
   <ref spec=ECMA262></p>