Merge 138863

Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp

Index: Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp
===================================================================
--- Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp	(revision 139380)
+++ Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp	(working copy)
@@ -1338,8 +1338,13 @@
 
         document()->setParsing(false); // Make the document think it's done, so it will apply XSL stylesheets.
         document()->styleResolverChanged(RecalcStyleImmediately);
+
+        // styleResolverChanged() call can detach the parser and null out its document.
+        // In that case, we just bail out.
+        if (isDetached())
+            return;
+
         document()->setParsing(true);
-
         DocumentParser::stopParsing();
     }
 #endif