Add has cross-site ancestor to environment settings objects

This helps with the HTTP WG's layered cookies draft integration work. whatwg/fetch#1807 depends on this state being available in so we can define SameSite properly.

Corresponding Service Worker PR: w3c/ServiceWorker#1775.

Author: bvandersloot-mozilla

source

@@ -92944,6 +92944,30 @@ interface <dfn interface>BarProp</dfn> {
       <span data-x="concept-document-window">associated <code>Document</code></span>.</p>
      </dd>
 
+     <dt>The <span data-x="concept-settings-object-has-cross-site-ancestor">has cross-site
+     ancestor</span></dt>
+     <dd>
+      <ol>
+       <li><p>If <var>window</var>'s <span>navigable</span>'s <span
+       data-x="nav-parent">parent</span> is null, then return false.</p></li>
+
+       <li><p>Let <var>parentDocument</var> be <var>window</var>'s <span>navigable</span>'s <span
+       data-x="nav-parent">parent</span>'s <span data-x="nav-document">active
+       document</span>.</p></li>
+
+       <li><p>If <var>parentDocument</var>'s <span>relevant settings object</span>'s <span
+       data-x="concept-settings-object-has-cross-site-ancestor">has cross-site ancestor</span> is
+       true, then return true.</p></li>
+
+       <li><p>If <var>parentDocument</var>'s <span data-x="concept-document-origin">origin</span>
+       is not <span>same site</span> with <var>window</var>'s <span
+       data-x="concept-document-window">associated <code>Document</code></span>'s <span
+       data-x="concept-document-origin">origin</span>, then return true.</p></li>
+
+       <li><p>Return false.</p></li>
+      </ol>
+     </dd>
+
      <dt>The <span data-x="concept-settings-object-policy-container">policy container</span></dt>
      <dd>
       <p>Return the <span data-x="concept-document-policy-container">policy container</span> of
@@ -108943,6 +108967,10 @@ new PaymentRequest(&hellip;); // Allowed to use
     <p>An <span>origin</span> used in security checks.</p>
    </dd>
 
+   <dt>A <dfn data-x="concept-settings-object-has-cross-site-ancestor" export
+   for="environment settings object">has cross-site ancestor</dfn></dt>
+   <dd><p>A boolean used in security checks.</p></dd>
+
    <dt>A <dfn data-x="concept-settings-object-policy-container" export
    for="environment settings object">policy container</dfn></dt>
 
@@ -123766,6 +123794,23 @@ interface <dfn interface>SharedWorkerGlobalScope</dfn> : <span>WorkerGlobalScope
       origin</var> otherwise.</p>
      </dd>
 
+     <dt>The <span data-x="concept-settings-object-has-cross-site-ancestor">has cross-site
+     ancestry</span></dt>
+     <dd>
+      <ol>
+       <li><p>If <var>outside settings</var>'s <span
+       data-x="concept-settings-object-has-cross-site-ancestor">has cross-site ancestor</span> is
+       true, then return true.</p></li>
+
+       <li><p>If <var>worker global scope</var>'s <span
+       data-x="concept-WorkerGlobalScope-url">url</span>'s <span
+       data-x="concept-url-scheme">scheme</span> is "<code data-x="">data</code>", then return
+       true.</p></li>
+
+       <li><p>Return false.</p></li>
+      </ol>
+     </dd>
+
      <dt>The <span data-x="concept-settings-object-policy-container">policy container</span></dt>
      <dd>
       <p>Return <var>worker global scope</var>'s <span
@@ -124986,6 +125031,10 @@ interface <dfn interface>WorkletGlobalScope</dfn> {};</code></pre>
       <p>Return <var>origin</var>.</p>
      </dd>
 
+     <dt>The <span data-x="concept-settings-object-has-cross-site-ancestor">has cross-site
+     ancestor</span></dt>
+     <dd><p>Return true.</p></dd>
+
      <dt>The <span data-x="concept-settings-object-policy-container">policy container</span></dt>
      <dd>
       <p>Return <var>inheritedPolicyContainer</var>.</p>
@@ -148319,6 +148368,7 @@ INSERT INTERFACES HERE
   Ben Millard,
   Benjamin Carl Wiley Sittler,
   Benjamin Hawkes-Lewis,
+  Benjamin VanderSloot,
   Benji Bilheimer, <!-- benjibee on GitHub -->
   Benoit Ren,
   Bert Bos,