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 278ff06b6df00c0f7c6682e6dc70e5f9117aa008..b67619728ddb2913029ab2d3aeb3533723c390a9 100644
--- a/Source/web/WebAXObject.cpp
+++ b/Source/web/WebAXObject.cpp
@@ -389,6 +389,14 @@ 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())