Add a new role for an iframe element with role=presentation.

Source/modules/accessibility/AXRenderObject.cpp

Index: Source/modules/accessibility/AXRenderObject.cpp
diff --git a/Source/modules/accessibility/AXRenderObject.cpp b/Source/modules/accessibility/AXRenderObject.cpp
index 91486f739aed8dbb5dd1c3558dc45cf47de2acb6..dad5bff6c5d340eb100d5258322fc909b5d6ecb4 100644
--- a/Source/modules/accessibility/AXRenderObject.cpp
+++ b/Source/modules/accessibility/AXRenderObject.cpp
@@ -427,8 +427,12 @@ AccessibilityRole AXRenderObject::determineAccessibilityRole()
     if (isHTMLHtmlElement(node))
         return IgnoredRole;
 
-    if (node && node->hasTagName(iframeTag))
+    if (node && node->hasTagName(iframeTag)) {
+        const AtomicString& ariaRole = getAttribute(roleAttr);
+        if (ariaRole == "none" || ariaRole == "presentation")
+            return IframePresentationalRole;
         return IframeRole;
+    }
 
     if (isEmbeddedObject())
         return EmbeddedObjectRole;