Fire AX notifications on list box options.

Source/modules/accessibility/AXListBox.cpp

 /*
  * Copyright (C) 2008 Apple 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 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "modules/accessibility/AXListBox.h"
 
+#include "core/html/HTMLOptionElement.h"
+#include "core/html/HTMLSelectElement.h"
 #include "core/layout/LayoutListBox.h"
 #include "modules/accessibility/AXListBoxOption.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 AXListBox::AXListBox(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
     : AXLayoutObject(layoutObject, axObjectCache)
+    , m_activeIndex(-1)
 {
+    activeIndexChanged();
 }
 
 AXListBox::~AXListBox()
 {
 }
 
 PassRefPtr<AXListBox> AXListBox::create(LayoutObject* layoutObject, AXObjectCacheImpl* axObjectCache)
 {
     return adoptRef(new AXListBox(layoutObject, axObjectCache));
 }
 
 AccessibilityRole AXListBox::roleValue() const
 {
     AccessibilityRole ariaRole = ariaRoleAttribute();
     if (ariaRole != UnknownRole)
         return ariaRole;
     return ListBoxRole;
 }
 
+AXObject* AXListBox::activeDescendant() const
+{
+    if (!isHTMLSelectElement(node()))
+        return nullptr;
+
+    HTMLSelectElement* select = toHTMLSelectElement(node());
+    int activeIndex = select->activeSelectionEndListIndex();
+    if (activeIndex >= 0 && activeIndex < static_cast<int>(select->length())) {
+        HTMLOptionElement* option = select->item(m_activeIndex);
+        return axObjectCache()->get(option);
+    }
+
+    return nullptr;
+}
+
+void AXListBox::activeIndexChanged()
+{
+    if (!isHTMLSelectElement(node()))
+        return;
+
+    HTMLSelectElement* select = toHTMLSelectElement(node());
+    int activeIndex = select->activeSelectionEndListIndex();
+    if (activeIndex == m_activeIndex)
+        return;
+
+    m_activeIndex = activeIndex;
+    if (!select->focused())
+        return;
+
+    if (m_activeIndex >= 0 && m_activeIndex < static_cast<int>(select->length())) {
+        HTMLOptionElement* option = select->item(m_activeIndex);
+        axObjectCache()->postNotification(option, AXObjectCacheImpl::AXFocusedUIElementChanged);
+    } else {
+        axObjectCache()->postNotification(this, AXObjectCacheImpl::AXFocusedUIElementChanged);
+    }
+}
+
 } // namespace blink