Inform WebDriver BiDi when a navigable is created or destroyed

See w3c/webdriver-bidi#708.

source

@@ -4518,6 +4518,8 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-fragment-navigated">WebDriver BiDi fragment navigated</dfn></li>
      <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-dom-content-loaded">WebDriver BiDi DOM content loaded</dfn></li>
      <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-load-complete">WebDriver BiDi load complete</dfn></li>
+     <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-navigable-created">WebDriver BiDi navigable created</dfn></li>
+     <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-navigable-destroyed">WebDriver BiDi navigable destroyed</dfn></li>
      <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-user-prompt-closed">WebDriver BiDi user prompt closed</dfn></li>
      <li><dfn data-x-href="https://w3c.github.io/webdriver-bidi/#webdriver-bidi-user-prompt-opened">WebDriver BiDi user prompt opened</dfn></li>
     </ul>
@@ -96024,6 +96026,8 @@ interface <dfn interface>NotRestoredReasons</dfn> {
    <li><p><span data-x="list append">Append</span> <var>traversable</var> to the user agent's
    <span>top-level traversable set</span>.</p></li>
 
+   <li><p>Invoke <span>WebDriver BiDi navigable created</span> with <var>traversable</var>.</p></li>
+
    <li><p>Return <var>traversable</var>.</p></li>
   </ol>
 
@@ -96219,6 +96223,8 @@ interface <dfn interface>NotRestoredReasons</dfn> {
      <var>traversable</var>.</p></li>
     </ol>
    </li>
+
+   <li><p>Invoke <span>WebDriver BiDi navigable created</span> with <var>traversable</var>.</p></li>
   </ol>
 
 
@@ -96422,6 +96428,9 @@ interface <dfn interface>NotRestoredReasons</dfn> {
 
    <li><p>If <var>navigable</var> is null, then return.</p></li>
 
+   <li><p>Let <var>browsingContext</var> be <var>navigable</var>'s <span
+   data-x="nav-bc">active browsing context</span>.</p></li>
+
    <li><p>Set <var>container</var>'s <span>content navigable</span> to null.</p></li>
 
    <li><p><span>Inform the navigation API about child navigable destruction</span> given
@@ -96451,6 +96460,9 @@ interface <dfn interface>NotRestoredReasons</dfn> {
      <var>traversable</var>.</p></li>
     </ol>
    </li>
+
+   <li><p>Invoke <span>WebDriver BiDi navigable destroyed</span> with <var>navigable</var>
+   and <var>browsingContext</var>.</p></li>
   </ol>
 
   <p>To <dfn>destroy a top-level traversable</dfn> given a <span>top-level traversable</span>
@@ -96481,6 +96493,9 @@ interface <dfn interface>NotRestoredReasons</dfn> {
 
    <li><p><span data-x="list remove">Remove</span> <var>traversable</var> from the user agent's
    <span>top-level traversable set</span>.</p></li>
+
+   <li><p>Invoke <span>WebDriver BiDi navigable destroyed</span> with <var>traversable</var>
+   and <var>browsingContext</var>.</p></li>
   </ol>
 
   <p>User agents may <span>destroy a top-level traversable</span> at any time (typically, <a