Introduce new API orientation() to expose aria-orientation correctly.

Source/web/WebAXObject.cpp

Index: Source/web/WebAXObject.cpp
diff --git a/Source/web/WebAXObject.cpp b/Source/web/WebAXObject.cpp
index dd76e7bf33d77fea65dc31c96b96430023dbfd8f..0d04227c7233148f516b1b1742778121a8361636 100644
--- a/Source/web/WebAXObject.cpp
+++ b/Source/web/WebAXObject.cpp
@@ -397,6 +397,14 @@ bool WebAXObject::isVertical() const
     return m_private->orientation() == AccessibilityOrientationVertical;
 }
 
+WebAXOrientation WebAXObject::orientation() const
+{
+    if (isDetached())
+        return WebAXOrientationUndefined;
+
+    return static_cast<WebAXOrientation>(m_private->orientation());
+}
+
 bool WebAXObject::isVisible() const
 {
     if (isDetached())