Handle case when XSL stylesheet node is removed during load

Source/core/dom/ProcessingInstruction.cpp

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 265 matching lines @@
     if (m_isCSS)
         document().styleEngine()->removeStyleSheetCandidateNode(this);
     else if (m_isXSL)
         document().styleEngine()->removeXSLStyleSheet(this);
 
     RefPtrWillBeRawPtr<StyleSheet> removedSheet = m_sheet;
 
     if (m_sheet) {
         ASSERT(m_sheet->ownerNode() == this);
         clearSheet();
+    } else if (resource()) {
+        ASSERT(m_loading);
+        document().styleEngine()->removePendingSheet(this);
+        clearResource();
     }
 
     // If we're in document teardown, then we don't need to do any notification of our sheet's removal.
     if (document().isActive())
         document().removedStyleSheet(removedSheet.get());
 }
 
 void ProcessingInstruction::clearSheet()
 {
     ASSERT(m_sheet);
     if (m_sheet->isLoading())
         document().styleEngine()->removePendingSheet(this);
     m_sheet.release()->clearOwnerNode();
 }
 
 void ProcessingInstruction::trace(Visitor* visitor)
 {
     visitor->trace(m_sheet);
     CharacterData::trace(visitor);
 }
 
 } // namespace