Get rid of loops looking for the first Element ancestor

Source/core/accessibility/AXNodeObject.cpp

Index: Source/core/accessibility/AXNodeObject.cpp
diff --git a/Source/core/accessibility/AXNodeObject.cpp b/Source/core/accessibility/AXNodeObject.cpp
index f491712b61d56f1a5d2dc2cf3688dcaf4ad5975c..3661aa9e3093b528247ac76b69b75a377cfb2a01 100644
--- a/Source/core/accessibility/AXNodeObject.cpp
+++ b/Source/core/accessibility/AXNodeObject.cpp
@@ -397,8 +397,8 @@ Element* AXNodeObject::mouseButtonListener() const
         return 0;
 
     // check if our parent is a mouse button listener
-    while (node && !node->isElementNode())
-        node = node->parentNode();
+    if (!node->isElementNode())
+        node = node->parentElement();
 
     if (!node)
         return 0;