[css-nav-1] Update the algorithm to reflect spatial-navigation-action

Author: frivoal

css-nav-1/Overview.bs

@@ -975,29 +975,43 @@ To run the <dfn>spatial navigation steps</dfn> in <var>direction</var>, do the f
 4. If <var>eventTarget</var> is the <a>Document</a> or the <a>document element</a>,
         set <var>eventTarget</var> be <a>the body element</a> if it is not <code>null</code>
         or to the <a>document element</a> otherwise.
-5. If <var>searchOrigin</var> is either a <a>scroll container</a> or the <a>document</a>
-    1. Let <var>candidates</var> be the result of <a>finding focusable areas</a>
-        within <var>searchOrigin</var>
-    2.
-        * If <var>candidates</var> contains at least 1 item:
-            1. Let <var>bestCandidate</var> be the result of <a>selecting the best candidate</a>
-                within <var>candidates</var> in <var>direction</var> starting from <var>searchOrigin</var>
-            2. If <a>navigation-override</a> <a>is enabled</a> in the [=node document=] of <var>eventTarget</var> for the <a spec=html for="/">origin</a> of the [=active document=] of the [=top-level browsing context=], then
-                <span class=api><a>fire an event</a> named <a event>navbeforefocus</a> at <var>eventTarget</var> using {{NavigationEvent}} with:
-                * {{NavigationEvent/dir}} set to <var>direction</var>
-                * {{NavigationEvent/relatedTarget}} set to <var>bestCandidate</var>
-                * the <code>bubbles</code> and <code>cancelable</code> attributes set to <code>true</code>
-
-                and return if the result is <code>false</code>.</span>
-            3. Run the <a>focusing steps</a> for <var>bestCandidate</var> and return
-        * Else if <var>eventTarget</var> <a>can be manually scrolled</a>,
-            <a>directionally scroll the element</a> <var>eventTarget</var> in <var>direction</var> and return.
-        * Else, fallback to the next step.
+5.
+    * If <var>searchOrigin</var> is <a>scroll container</a>
+        and the computed value of the 'spatial-navigation-action' property on <var>searchOrigin</var> is ''spatial-navigation-action/scroll''
+        and <var>searchOrigin</var> [=can be manually scrolled=],
+        then [=directionally scroll the element=] <var>searchOrigin</var> and return.
+    * Else, if <var>searchOrigin</var> is either a <a>scroll container</a> or the <a>document</a>
+        1. Let <var>candidates</var> be the result of <a>finding focusable areas</a>
+            within <var>searchOrigin</var>
+            with the argument set to <code>false</code> if computed value of the 'spatial-navigation-action' property on <var>searchOrigin</var> is ''spatial-navigation-action/focus''
+            or to <code>true</code> otherwise.
+        2.
+            * If <var>candidates</var> contains at least 1 item:
+                1. Let <var>bestCandidate</var> be the result of <a>selecting the best candidate</a>
+                    within <var>candidates</var> in <var>direction</var> starting from <var>searchOrigin</var>
+                2. If <a>navigation-override</a> <a>is enabled</a> in the [=node document=] of <var>eventTarget</var> for the <a spec=html for="/">origin</a> of the [=active document=] of the [=top-level browsing context=], then
+                    <span class=api><a>fire an event</a> named <a event>navbeforefocus</a> at <var>eventTarget</var> using {{NavigationEvent}} with:
+                    * {{NavigationEvent/dir}} set to <var>direction</var>
+                    * {{NavigationEvent/relatedTarget}} set to <var>bestCandidate</var>
+                    * the <code>bubbles</code> and <code>cancelable</code> attributes set to <code>true</code>
+
+                    and return if the result is <code>false</code>.</span>
+                3. Run the <a>focusing steps</a> for <var>bestCandidate</var> and return
+            * Else if the computed value of the 'spatial-navigation-action' property on <var>eventTarget</var> is not ''spatial-navigation-action/focus''
+                and <var>eventTarget</var> <a>can be manually scrolled</a>,
+                then <a>directionally scroll the element</a> <var>eventTarget</var> in <var>direction</var> and return.
+            * Else, fallback to the next step.
+    * Else, fallback to the next step.
 6. Let <var>container</var> be the nearest ancestor of <var>eventTarget</var> that is a <a>spatial navigation container</a>.
 7. <i>Loop</i>: Let <var>candidates</var> be the result of <a>finding focusable areas</a>
-    within <var>container</var>, excluding <var>searchOrigin</var>
+    within <var>container</var>
+    with the argument set to <code>false</code>
+    if computed value of the 'spatial-navigation-action' property on <var>container</var> is ''spatial-navigation-action/focus''
+    or to <code>true</code> otherwise,
+    excluding <var>searchOrigin</var>
 8. If <var>candidates</var> is empty:
-    * If <var>container</var> is a <a>scroll container</a> that <a>can be manually scrolled</a>,
+    * If the computed value of the 'spatial-navigation-action' property on <var>container</var> is not ''spatial-navigation-action/focus''
+        and <var>container</var> is a <a>scroll container</a> that <a>can be manually scrolled</a>,
         <a>directionally scroll the element</a> <var>container</var> in <var>direction</var> and return.
     * Else,
         1. If <a>navigation-override</a> <a>is enabled</a> in the [=node document=] of <var>eventTarget</var> for the <a spec=html for="/">origin</a> of the [=active document=] of the [=top-level browsing context=], then