Selection follows focus/activedescendant in single selection containers

third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 522 matching lines @@
     if (type == InputTypeNames::time)
       return kInputTimeRole;
     return kTextFieldRole;
   }
 
   if (isHTMLSelectElement(*GetNode())) {
     HTMLSelectElement& select_element = toHTMLSelectElement(*GetNode());
     return select_element.IsMultiple() ? kListBoxRole : kPopUpButtonRole;
   }
 
+  if (isHTMLOptionElement(*GetNode())) {
+    HTMLSelectElement* select_element =
+        toHTMLOptionElement(GetNode())->OwnerSelectElement();
+    return select_element->IsMultiple() ? kListBoxOptionRole
+                                        : kMenuListOptionRole;
+  }
+
   if (isHTMLTextAreaElement(*GetNode()))
     return kTextFieldRole;
 
   if (HeadingLevel())
     return kHeadingRole;
 
   if (isHTMLDivElement(*GetNode()))
     return kGenericContainerRole;
 
   if (isHTMLMeterElement(*GetNode()))
@@ skipping 729 matching lines @@
   if (!IsPresentational() && AriaRoleAttribute() != kUnknownRole &&
       AncestorExposesActiveDescendant())
     return true;
 
   // NOTE: It would be more accurate to ask the document whether
   // setFocusedNode() would do anything. For example, setFocusedNode() will do
   // nothing if the current focused node will not relinquish the focus.
   if (IsDisabledFormControl(node))
     return false;
 
+  // Check for options here because AXListBoxOption and AXMenuListOption
+  // don't help when the <option> is canvas fallback, and because
+  // a common case for aria-owns from a textbox that points to a list
+  // does not change the hierarchy (textboxes don't suport children)
+  if ((RoleValue() == kListBoxOptionRole ||
+       RoleValue() == kMenuListOptionRole) &&
+      IsEnabled())
+    return true;
+
   return node->IsElementNode() && ToElement(node)->SupportsFocus();
 }
 
 bool AXNodeObject::CanSetValueAttribute() const {
   if (AOMPropertyOrARIAAttributeIsTrue(AOMBooleanProperty::kReadOnly))
     return false;
 
   if (IsProgressIndicator() || IsSlider())
     return true;
 
   if (IsTextControl() && !IsNativeTextControl())
     return true;
 
   // Any node could be contenteditable, so isReadOnly should be relied upon
   // for this information for all elements.
   return !IsReadOnly();
 }
 
 bool AXNodeObject::CanSetSelectedAttribute() const {
-  // ARIA list box options can be selected if they are children of an element
-  // with an aria-activedescendant attribute.
-  if (AriaRoleAttribute() == kListBoxOptionRole &&
-      AncestorExposesActiveDescendant())
+  const AccessibilityRole role = AriaRoleAttribute();
+  // These elements can be selected if not disabled (native or ARIA)
+  if ((role == kListBoxOptionRole || role == kMenuListOptionRole ||
+       role == kTreeItemRole || role == kCellRole || role == kTabRole) &&

[David Tseng, 2017/06/06 21:28:47]

The spec includes the roles:

gridcell
option
row
tab
Inherits into Roles:	
columnheader
rowheader
treeitem

+      IsEnabled() && CanSetFocusAttribute()) {
     return true;
+  }
   return AXObjectImpl::CanSetSelectedAttribute();
 }
 
 bool AXNodeObject::CanvasHasFallbackContent() const {
   Node* node = this->GetNode();
   if (!isHTMLCanvasElement(node))
     return false;
 
   // If it has any children that are elements, we'll assume it might be fallback
   // content. If it has no children or its only children are not elements
@@ skipping 906 matching lines @@
   // If an element has an ARIA role of presentation, we need to consider the
   // native role when deciding whether it can have children or not - otherwise
   // giving something a role of presentation could expose inner implementation
   // details.
   if (IsPresentational())
     role = NativeAccessibilityRoleIgnoringAria();
 
   switch (role) {
     case kImageRole:
     case kButtonRole:
-    case kPopUpButtonRole:
     case kCheckBoxRole:
     case kRadioButtonRole:
     case kSwitchRole:
     case kTabRole:
     case kToggleButtonRole:
     case kListBoxOptionRole:
+    case kMenuButtonRole:
+    case kMenuListOptionRole:
     case kScrollBarRole:
       return false;
+    case kPopUpButtonRole:
+      return isHTMLSelectElement(GetNode());
     case kStaticTextRole:
       if (!AxObjectCache().InlineTextBoxAccessibilityEnabled())
         return false;
     default:
       return true;
   }
 }
 
 Element* AXNodeObject::ActionElement() const {
   Node* node = this->GetNode();
@@ skipping 968 matching lines @@
     return String();
   return ToTextControlElement(node)->StrippedPlaceholder();
 }
 
 DEFINE_TRACE(AXNodeObject) {
   visitor->Trace(node_);
   AXObjectImpl::Trace(visitor);
 }
 
 }  // namespace blink