Refresh selected state on active descendants

Items in single selection containers that have accessibility focus
should get the selected state. Code to mirror focus to selection exists,
but the selected state must be refreshed.

Bug: 846089
Change-Id: I90eb6aaec3be196b78126241ebf7e3d38ccda7c2
Reviewed-on: https://chromium-review.googlesource.com/1070520
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561353}

content/test/data/accessibility/event/aria-combo-box-expand-expected-mac.txt

 AXExpandedChanged on AXComboBox
 AXSelectedChildrenChanged on AXComboBox
+AXSelectedChildrenChanged on AXList

content/test/data/accessibility/event/aria-combo-box-expand-expected-win.txt

-EVENT_OBJECT_FOCUS on <li#option1> role=ROLE_SYSTEM_LISTITEM name="Apple" FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_FOCUS on <li#option1> role=ROLE_SYSTEM_LISTITEM name="Apple" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTION on <li#option1> role=ROLE_SYSTEM_LISTITEM name="Apple" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTIONWITHIN on <ul#list> role=ROLE_SYSTEM_LIST IA2_STATE_VERTICAL
 EVENT_OBJECT_STATECHANGE on <input> role=ROLE_SYSTEM_COMBOBOX EXPANDED,FOCUSABLE,HASPOPUP IA2_STATE_EDITABLE,IA2_STATE_SELECTABLE_TEXT,IA2_STATE_SINGLE_LINE,IA2_STATE_SUPPORTS_AUTOCOMPLETION
+EVENT_OBJECT_STATECHANGE on <li#option1> role=ROLE_SYSTEM_LISTITEM name="Apple" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE
 IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on <input> role=ROLE_SYSTEM_COMBOBOX EXPANDED,FOCUSABLE,HASPOPUP IA2_STATE_EDITABLE,IA2_STATE_SELECTABLE_TEXT,IA2_STATE_SINGLE_LINE,IA2_STATE_SUPPORTS_AUTOCOMPLETION

content/test/data/accessibility/event/aria-combo-box-focus-expected-win.txt

-EVENT_OBJECT_FOCUS on role=ROLE_SYSTEM_LISTITEM name="Apple" FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_FOCUS on role=ROLE_SYSTEM_LISTITEM name="Apple" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTION on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTIONWITHIN on <ul#list> role=ROLE_SYSTEM_LIST IA2_STATE_VERTICAL
+EVENT_OBJECT_STATECHANGE on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE
 IA2_EVENT_TEXT_CARET_MOVED on role=ROLE_SYSTEM_COMBOBOX EXPANDED,FOCUSABLE,HASPOPUP IA2_STATE_EDITABLE,IA2_STATE_SELECTABLE_TEXT,IA2_STATE_SINGLE_LINE,IA2_STATE_SUPPORTS_AUTOCOMPLETION

content/test/data/accessibility/event/aria-combo-box-next-expected-mac.txt

 AXSelectedChildrenChanged on AXComboBox
+AXSelectedChildrenChanged on AXList

content/test/data/accessibility/event/aria-combo-box-next-expected-win.txt

-EVENT_OBJECT_FOCUS on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_FOCUS on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTION on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE
+EVENT_OBJECT_SELECTIONWITHIN on <ul#list> role=ROLE_SYSTEM_LIST IA2_STATE_VERTICAL
+EVENT_OBJECT_STATECHANGE on <li#option3> role=ROLE_SYSTEM_LISTITEM name="Banana" SELECTED,FOCUSABLE,SELECTABLE
 IA2_EVENT_ACTIVE_DESCENDANT_CHANGED on <input> role=ROLE_SYSTEM_COMBOBOX EXPANDED,FOCUSABLE,HASPOPUP IA2_STATE_EDITABLE,IA2_STATE_SELECTABLE_TEXT,IA2_STATE_SINGLE_LINE,IA2_STATE_SUPPORTS_AUTOCOMPLETION

content/test/data/accessibility/event/aria-treeitem-focus-expected-mac.txt

 AXFocusedUIElementChanged on AXRow AXTitle="Minor Ninth"
+AXSelectedChildrenChanged on AXOutline
 AXSelectedRowsChanged on AXOutline

third_party/blink/renderer/modules/accessibility/ax_layout_object.cc

@@ -458,16 +458,29 @@ AccessibilitySelectedState AXLayoutObject::IsSelected() const {
 
   // Selection follows focus, but ONLY in single selection containers,
   // and only if aria-selected was not present to override
+  return IsSelectedFromFocus() ? kSelectedStateTrue : kSelectedStateFalse;
+}
 
+// In single selection containers, selection follows focus unless aria_selected
+// is set to false.
+bool AXLayoutObject::IsSelectedFromFocus() const {
+  // If not a single selection container, selection does not follow focus.
   AXObject* container = ContainerWidget();
   if (!container || container->IsMultiSelectable())
-    return kSelectedStateFalse;
+    return false;
 
+  // If this object is not accessibility focused, then it is not selected from
+  // focus.
   AXObject* focused_object = AXObjectCache().FocusedObject();
-  return (focused_object == this ||
-          (focused_object && focused_object->ActiveDescendant() == this))
-             ? kSelectedStateTrue
-             : kSelectedStateFalse;
+  if (focused_object != this &&
+      (!focused_object || focused_object->ActiveDescendant() != this))
+    return false;
+
+  // In single selection container and accessibility focused => true if
+  // aria-selected wasn't used as an override.
+  bool is_selected;
+  return !HasAOMPropertyOrARIAAttribute(AOMBooleanProperty::kSelected,
+                                        is_selected);
 }
 
 //
@@ -2214,8 +2227,21 @@ void AXLayoutObject::HandleActiveDescendantChanged() {
   if (!GetLayoutObject())
     return;
 
+  Vector<String> ids;
+  TokenVectorFromAttribute(ids, aria_activedescendantAttr);
+  if (!ids.IsEmpty())
+    AXObjectCache().UpdateReverseRelations(this, ids);
+
   AXObject* focused_object = AXObjectCache().FocusedObject();
   if (focused_object == this && SupportsARIAActiveDescendant()) {
+    AXObject* active_descendant = ActiveDescendant();
+    if (active_descendant && active_descendant->IsSelectedFromFocus()) {
+      // In single selection containers, selection follows focus, so a selection
+      // changed event must be fired. This ensures the AT is notified that the
+      // selected state has changed, so that it does not read "unselected" as
+      // the user navigates through the items.
+      AXObjectCache().HandleAriaSelectedChanged(active_descendant->GetNode());
+    }
     AXObjectCache().PostNotification(
         GetLayoutObject(), AXObjectCacheImpl::kAXActiveDescendantChanged);
   }
@@ -2418,7 +2444,6 @@ void AXLayoutObject::LineBreaks(Vector<int>& line_breaks) const {
 // Private.
 //
 
-
 bool AXLayoutObject::IsTabItemSelected() const {
   if (!IsTabItem() || !GetLayoutObject())
     return false;

third_party/blink/renderer/modules/accessibility/ax_layout_object.h

@@ -86,6 +86,7 @@ class MODULES_EXPORT AXLayoutObject : public AXNodeObject {
   // Check object state.
   bool IsFocused() const override;
   AccessibilitySelectedState IsSelected() const override;
+  bool IsSelectedFromFocus() const override;
 
   // Whether objects are ignored, i.e. not included in the tree.
   AXObjectInclusion DefaultObjectInclusion(

third_party/blink/renderer/modules/accessibility/ax_object.h

@@ -379,6 +379,8 @@ class MODULES_EXPORT AXObject : public GarbageCollectedFinalized<AXObject> {
   virtual AccessibilitySelectedState IsSelected() const {
     return kSelectedStateUndefined;
   }
+  // Is the object selected because selection is following focus?
+  virtual bool IsSelectedFromFocus() const { return false; }
   virtual bool IsSelectedOptionActive() const { return false; }
   virtual bool IsVisible() const { return true; }
   virtual bool IsVisited() const { return false; }