Added ability to distinguished between rich and plain text editables on accessibility objects.

Source/web/WebAXObject.cpp

Index: Source/web/WebAXObject.cpp
diff --git a/Source/web/WebAXObject.cpp b/Source/web/WebAXObject.cpp
index 92be6de0e4d73a47af21c8f07de6fb52c2778158..92276f3bf958498dc378a41fc48e67a4fd565664 100644
--- a/Source/web/WebAXObject.cpp
+++ b/Source/web/WebAXObject.cpp
@@ -536,6 +536,14 @@ bool WebAXObject::isMultiline() const
     return m_private->isMultiline();
 }
 
+bool WebAXObject::isContentRichlyEditable() const
+{
+    if (isDetached())
+        return false;
+
+    return m_private->isContentRichlyEditable();
+}
+
 int WebAXObject::posInSet() const
 {
     if (isDetached())