Redact ancestorOrigins using "the document's referrer"

source

@@ -2521,6 +2521,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
              <dfn data-x="set append" data-x-href="https://infra.spec.whatwg.org/#set-append">append</dfn></li>
      <li>The <dfn data-x-href="https://infra.spec.whatwg.org/#struct">struct</dfn> specification type and the associated definition for
              <dfn data-x="struct item" data-x-href="https://infra.spec.whatwg.org/#struct-item">item</dfn></li>
+     <li>The <dfn data-x-href="https://infra.spec.whatwg.org/#tuple">tuple</dfn> data structure</li>
      <li>The <dfn data-x-href="https://infra.spec.whatwg.org/#forgiving-base64-encode">forgiving-base64 encode</dfn> and
              <dfn data-x-href="https://infra.spec.whatwg.org/#forgiving-base64-decode">forgiving-base64 decode</dfn> algorithms</li>
      <li><dfn data-x-href="https://infra.spec.whatwg.org/#html-namespace">HTML namespace</dfn></li>
@@ -80996,26 +80997,82 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
   the following steps would produce:</p>
 
   <ol>
-   <li><p>Let <var>output</var> be a new <span>list</span> of strings.</p></li>
+   <li><p>Let <var>parentOrigins</var> be a new <span>list</span> of <span
+   data-x="tuple">tuples</span> consisting of <dfn data-x="tuple parent's origin">parent's
+   origin</dfn> and <dfn data-x="tuple referrer">referrer</dfn>.</p></li>
 
    <li><p>Let <var>current</var> be the <span data-x="concept-document-bc">browsing context</span>
    of the <code>Document</code> with which this <code>Location</code> object is associated.</p></li>
+   <!-- All Location objects are associated with Document objects that have a browsing context upon
+        creation. -->
 
-   <li><p><i>Loop</i>: If <var>current</var> has no <span>parent browsing context</span>, jump to
-   the step labeled <i>end</i>.</p></li>
+   <li>
+    <p>While <var>current</var> has a <span>parent browsing context</span>:</p>
 
-   <li><p>Let <var>current</var> be <var>current</var>'s <span>parent browsing
-   context</span>.</p></li>
+    <ol>
+     <li><p><span data-x="list append">Append</span> (<var>current</var>'s <span>parent browsing
+     context</span>'s <span>active document</span>'s <span>origin</span>, <var>current</var>'s
+     <span>active document</span>'s <span data-x="the document's referrer">referrer</span>) to
+     <var>parentOrigins</var>.</p></li>
 
-   <li><p><span data-x="list append">Append</span> the <span data-x="serialization of an
-   origin">serialization</span> of <var>current</var>'s <span>active document</span>'s
-   <span>origin</span> to <var>output</var>.</p></li>
+     <li><p>Set <var>current</var> to <var>current</var>'s <span>parent browsing
+     context</span>.</p></li>
+    </ol>
+   </li>
 
-   <li><p>Return to the step labeled <i>loop</i>.</p></li>
+   <li><p>Let <var>output</var> be a new <span>list</span> of strings.</p></li>
+
+   <li><p>Let <var>lastRedactedOrigin</var> be null.</p></li>
+
+   <li>
+    <p><span data-x="list iterate">For each</span> <var>tuple</var> in <var>parentOrigins</var>:</p>
+
+    <ol>
+     <li><p>If <var>lastRedactedOrigin</var> is not null and <var>tuple</var>'s <span data-x="tuple
+     parent's origin">parent's origin</span> is <span>same origin</span> with
+     <var>lastRedactedOrigin</var>, then <span data-x="list append">append</span>
+     "<code data-x="">null</code>" to <var>output</var> and <span>continue</span>.</p></li>
+
+     <li><p>Set <var>lastRedactedOrigin</var> to null.</p></li>
+
+     <li><p>Let <var>origin</var> be null.</p></li>
 
-   <li><p><i>End</i>: Return <var>output</var>.</p></li>
+     <li>
+      <p>If <var>tuple</var>'s <span data-x="tuple referrer">referrer</span> is not the empty
+      string, then:</p>
+
+      <ol>
+       <li><p>Let <var>referrerURL</var> be the result of <span data-x="URL parser">parsing</span>
+       <var>tuple</var>'s <span data-x="tuple referrer">referrer</span>.</p></li>
+
+       <li><p>Assert: <var>referrerURL</var> is not failure.</p></li>
+
+       <li><p>Set <var>origin</var> to <var>referrerURL</var>'s <span
+       data-x="concept-url-origin">origin</span>.</p></li>
+      </ol>
+     </li>
+
+     <li><p>If <var>origin</var> is null or <var>tuple</var>'s <span data-x="tuple parent's
+     origin">parent's origin</span> is not <span>same origin</span> with <var>origin</var>, then set
+     <var>lastRedactedOrigin</var> to <var>tuple</var>'s <span data-x="tuple parent's
+     origin">parent's origin</span> and <span data-x="list append">append</span> "<code
+     data-x="">null</code>" to <var>output</var>.</p></li>
+
+     <li><p>Otherwise, <span data-x="list append">append</span> the <span data-x="serialization of
+     an origin">serialization</span> of <var>tuple</var>'s <span data-x="tuple parent's
+     origin">parent's origin</span> to <var>output</var>.</p></li>
+    </ol>
+   </li>
+
+   <li><p>Return <var>output</var>.</p></li>
   </ol>
 
+  <p class="note">The reliance on <span data-x="browsing context">browsing contexts</span> and their
+  <span>active document</span> in this algorithm is safe as the <span>active document</span> is the
+  <code>Document</code> object that the <span data-x="browsing context">browsing contexts</span> are
+  <span data-x="browsing context nested through">nested through</span>, and both are available when
+  a <code>Location</code> object is created at which point this algorithm is run.</p>
+
   <p>A <code>Location</code> object has an associated <dfn><code>Location</code>-object-setter
   navigate</dfn> algorithm, which given a <var>url</var>, runs these steps:</p>
 
@@ -81538,11 +81595,6 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
    data-x="concept-location-ancestor-origins-list">ancestor origins list</span>.</p></li>
   </ol>
 
-  <p class="warning">The details of how the <code
-  data-x="dom-location-ancestorOrigins">ancestorOrigins</code> attribute works are still
-  controversial and might change. See <a href="https://github.com/whatwg/html/issues/1918">issue
-  #1918</a> for more information.</p>
-
   <hr>
 
   <p id="location-internal-methods">As explained earlier, the <code>Location</code> exotic object