Navigation API: fix an ordering issue

Because navigatesuccess/navigateerror events can run JavaScript code, they can change the "ongoing API method tracker" pointer. Thus, it's better to resolve/reject the finished promise for the API method tracker before firing the event.

This does not change the observable order in normal cases: it remains the case that JavaScript event handlers for navigatesuccess/navigateerror run before promise reactions, because promise resolution is always delayed by a microtask. However, it fixes some tricky reentrant cases, which would otherwise cause spec assertion fails.

Author: domenic

source

@@ -96401,15 +96401,15 @@ const p2 = navigation.navigate(url2).finished;</code></pre>
     0.</p>
    </li>
 
+   <li><p>If <var>navigation</var>'s <span>ongoing API method tracker</span> is non-null, then
+   <span>reject the finished promise</span> for <var>apiMethodTracker</var> with
+   <var>error</var>.</p></li>
+
    <li><p><span data-x="concept-event-fire">Fire an event</span> named <code
    data-x="event-navigateerror">navigateerror</code> at <var>navigation</var> using
    <code>ErrorEvent</code>, with additional attributes initialized according to
    <var>errorInfo</var>.</p></li>
 
-   <li><p>If <var>navigation</var>'s <span>ongoing API method tracker</span> is non-null, then
-   <span>reject the finished promise</span> for <var>apiMethodTracker</var> with
-   <var>error</var>.</p></li>
-
    <li>
     <p>If <var>navigation</var>'s <span data-x="concept-Navigation-transition">transition</span> is
     not null, then:</p>
@@ -97265,7 +97265,7 @@ interface <dfn interface>NavigationDestination</dfn> {
       </ol>
 
       <div class="note">
-       <p>If there is an ongoing cross-document navigation, this means it will signaled to the
+       <p>If there is an ongoing cross-document navigation, this means it will be signaled to the
        navigation API as aborted, e.g., by firing <code
        data-x="event-navigateerror">navigateerror</code> events. This is somewhat accurate, since
        the next navigation the <code>Document</code> experiences will be this same-document
@@ -97743,12 +97743,12 @@ interface <dfn interface>NavigationDestination</dfn> {
        <li><p><span data-x="NavigateEvent-finish">Finish</span> <var>event</var> given
        true.</p></li>
 
-       <li><p><span data-x="concept-event-fire">Fire an event</span> named <code
-       data-x="event-navigatesuccess">navigatesuccess</code> at <var>navigation</var>.</p></li>
-
        <li><p>If <var>apiMethodTracker</var> is non-null, then <span>resolve the finished
        promise</span> for <var>apiMethodTracker</var>.</p></li>
 
+       <li><p><span data-x="concept-event-fire">Fire an event</span> named <code
+       data-x="event-navigatesuccess">navigatesuccess</code> at <var>navigation</var>.</p></li>
+
        <li><p>If <var>navigation</var>'s <span
        data-x="concept-Navigation-transition">transition</span> is not null, then resolve
        <var>navigation</var>'s <span data-x="concept-Navigation-transition">transition</span>'s
@@ -97782,14 +97782,14 @@ interface <dfn interface>NavigationDestination</dfn> {
        <li><p>Let <var>errorInfo</var> be the result of <span data-x="extract-error">extracting error
        information</span> from <var>rejectionReason</var>.</p></li>
 
+       <li><p>If <var>apiMethodTracker</var> is non-null, then <span>reject the finished
+       promise</span> for <var>apiMethodTracker</var> with <var>rejectionReason</var>.</p></li>
+
        <li><p><span data-x="concept-event-fire">Fire an event</span> named <code
        data-x="event-navigateerror">navigateerror</code> at <var>navigation</var> using
        <code>ErrorEvent</code>, with additional attributes initialized according to
        <var>errorInfo</var>.</p></li>
 
-       <li><p>If <var>apiMethodTracker</var> is non-null, then <span>reject the finished
-       promise</span> for <var>apiMethodTracker</var> with <var>rejectionReason</var>.</p></li>
-
        <li><p>If <var>navigation</var>'s <span
        data-x="concept-Navigation-transition">transition</span> is not null, then reject
        <var>navigation</var>'s <span data-x="concept-Navigation-transition">transition</span>'s