Carry over sticky activation for same-origin navs and traversals

See discussion in WICG/view-transitions#239 and #11328 (comment).

Author: domenic

source

@@ -80190,8 +80190,8 @@ interface <dfn interface>VisibilityStateEntry</dfn> : <span>PerformanceEntry</sp
 
   <h4 id="user-activation-data-model">Data model</h4>
 
-  <p>For the purpose of tracking user activation, each <code>Window</code> <var>W</var> has two
-  relevant values:</p>
+  <p>For the purpose of tracking user activation, each <code>Window</code> <var>W</var> has the
+  following relevant values:</p>
 
   <ul>
    <li><p>A <dfn>last activation timestamp</dfn>, which is either a
@@ -80201,6 +80201,8 @@ interface <dfn interface>VisibilityStateEntry</dfn> : <span>PerformanceEntry</sp
 
    <li><p>A <dfn>last history-action activation timestamp</dfn>, which is either a
    <code>DOMHighResTimeStamp</code> or positive infinity, initially positive infinity.</p></li>
+
+   <li><p>A <dfn>sticky activation override</dfn>, a boolean, initially false.</p></li>
   </ul>
 
   <p>A user agent also defines a <dfn>transient activation duration</dfn>, which is a constant
@@ -80217,12 +80219,14 @@ interface <dfn interface>VisibilityStateEntry</dfn> : <span>PerformanceEntry</sp
    <dt><dfn export>Sticky activation</dfn></dt>
    <dd>
     <p>When the <span>current high resolution time</span> given <var>W</var> is greater than or
-    equal to the <span>last activation timestamp</span> in <var>W</var>, <var>W</var> is said to
-    have <span>sticky activation</span>.</p>
+    equal to the <span>last activation timestamp</span> in <var>W</var>, or <var>W</var>'s
+    <span>sticky activation override</span> is true, <var>W</var> is said to have <span>sticky
+    activation</span>.</p>
 
     <p>This is <var>W</var>'s historical activation state, indicating whether the user has ever
     interacted in <var>W</var>. It starts false, then changes to true (and never changes back to
-    false) when <var>W</var> gets the very first <span>activation notification</span>.</p>
+    false) when <var>W</var> gets the very first <span>activation notification</span>. It is also
+    carried over between windows for same-origin navigations and traversals.</p>
    </dd>
 
    <dt><dfn export>Transient activation</dfn></dt>
@@ -106369,6 +106373,13 @@ location.href = '#foo';</code></pre>
      <var>realmExecutionContext</var>, <var>navigationParams</var>'s <span
      data-x="navigation-params-reserved-environment">reserved environment</span>,
      <var>topLevelCreationURL</var>, and <var>topLevelOrigin</var>.</p></li>
+
+     <li><p>If <var>navigable</var>'s <span data-x="nav-window">active window</span> has
+     <span>sticky activation</span>, and <var>navigable</var>'s <span data-x="nav-document">active
+     document</span>'s <span data-x="concept-document-origin">origin</span> is <span>same
+     origin</span> with <var>navigationParams</var>'s <span
+     data-x="navigation-params-origin">origin</span>, then set <var>window</var>'s <span>sticky
+     activation override</span> to true.</p></li>
     </ol>
 
     <p class="note">This is the usual case, where the new <code>Document</code> we're about to