[css-nav-1] Add the change section

Author: Jihye Hong

css-nav-1/Overview.bs

@@ -870,7 +870,7 @@ the <a spec=html for="/">origin</a> of the [=active document=] of the [=top-leve
         const candidates = e.relatedTarget.focusableAreas({'mode': 'all'});
 
         // Prevent default only when navigation direction is on y-axis
-        if (dirArray.includes(e.dir) && (candidates.length > 0)) {
+        if (verticalDir.includes(e.dir) && (candidates.length > 0)) {
             e.preventDefault();
 
             if (e.dir === 'down') {
@@ -964,7 +964,7 @@ they must not be set differently.
 <h3 id=grouping>
 Groupings of elements</h3>
 
-While the general model for spatial navigation
+While the processing model for spatial navigation
 is to work from the layout of the document
 and the relative position of focusable elements,
 the User Agent is required to prioritize finding elements
@@ -987,13 +987,17 @@ Additional <a>spatial navigation containers</a> can be created using the 'spatia
 <h3 id=nav>
 Navigation</h3>
 
+The processing model for spatial navigation describes how spatial navigation works in general.
+
 <figure class="verbose non-normative">
+    <object type="image/svg+xml" data="images/spatnav_processing_model_diagram.svg"></object>
     <figcaption>
+        Overview of the Spatial navigation processing model
+        <br>
         This figure is not normative.
         It gives an overview of the processing model further defined in this section,
         assuming that the 'spatial-navigation-action' property has its initial value of ''spatial-navigation-action/auto''.
     </figcaption>
-    <object type="image/svg+xml" data="images/spatnav_processing_model_diagram.svg"></object>
 </figure>
 
 <div algorithm="to run the spatial navigation steps">
@@ -1721,3 +1725,15 @@ The editors of this specification would like to thank the following individuals
 * Junho Seo
 * Rob Dodson
 * Seungcheon Baek
+
+<h2 class="no-num" id="changes">Changes</h2>
+
+<em>This section is non-normative.</em>
+
+	The following changes were made since the <a href="https://www.w3.org/TR/2019/WD-css-nav-1-20190423/">23 April 2019 First Public Working Draft</a>.
+    
+    * Changed the result of {{getSpatialNavigationContainer()}} to return the nearest <a>spatial navigation container</a> ancestor
+    * Added 'spatial-navigation-function'
+    * Added <a>updating the search origin</a> step
+    * Changed the IDL of {{spatialNavigationSearch()}} as separating the dir attribute from {{SpatialNavigationSearchOptions}}
+    * Made the focusable element fully overlapped with search origin which is not the <a>spatial navigation container</a> as a candidate for fixing the unreachability