Add scroll bubbling monkeypatches

spec.bs

@@ -144,6 +144,10 @@ spec: RFC8941; urlPrefix: https://www.rfc-editor.org/rfc/rfc8941.html
     text: structured header; url: #section-1
     for: structured header
       text: token; url: name-tokens
+spec: CSS; urlPrefix: https://www.w3.org/TR/cssom-view-1/
+  type: dfn
+    text: scroll a target into view; url: #scroll-an-element-into-view
+    text: run the scroll steps; url: document-run-the-scroll-steps
 spec: permissions-policy; urlPrefix: https://w3c.github.io/webappsec-permissions-policy
   type: dfn
     text: ASCII-serialized policy directive; url: serialized-policy-directive
@@ -2239,3 +2243,25 @@ achieve the outcomes described in the above explanatory content.
   /fenced-frame/permission-geolocation.https.html
   /fenced-frame/permission-notification.https.html
 </wpt>
+
+<h3 id=cssom-monkeypatch>CSSOM View</h3>
+
+The <a href=https://www.w3.org/TR/cssom-view-1>CSSOM View Module</a> defines scroll bubbling behavior
+through the [=scroll a target into view=] algorithm. Our specification modifies it to not allow
+scrolling a target into view if it is inside of a fenced frame.
+
+Modify the [=scroll a target into view=] algorithm to add 2 steps after step 1 that reads:
+
+2. If the <var ignore=''>target</var>-associated {{Document}}'s [=node navigable=]'s
+   [=navigable/traversable navigable=] is a [=fenced navigable container/fenced navigable=], terminate these steps.
+3. If the <var ignore=''>target</var>-associated {{Document}}'s [=Document/ancestor navigables=] contains
+   a [=navigable=] whose [=navigable/traversable navigable=] is a [=fenced navigable container/fenced navigable=],
+   terminate these steps.
+
+Modify the [=run the scroll steps=] algorithm to add a check after step 1.1 that reads:
+
+2. If <var ignore=''>target</var> is a {{Document}} whose [=node navigable=]'s
+   [=navigable/traversable navigable=] is a [=fenced navigable container/fenced navigable=],
+   continue.
+
+Note: This ensures that scroll events do not affect fenced frames.