Oilpan: Move the EventListener hierarchy to Oilpan's heap

Source/core/dom/ProcessingInstruction.cpp

Index: Source/core/dom/ProcessingInstruction.cpp
diff --git a/Source/core/dom/ProcessingInstruction.cpp b/Source/core/dom/ProcessingInstruction.cpp
index a4cc838d633af219f8fe5414c0f0fcc023ebc0e6..cbe3e6c9c66a70d77e877de0e59c18b746d7f388 100644
--- a/Source/core/dom/ProcessingInstruction.cpp
+++ b/Source/core/dom/ProcessingInstruction.cpp
@@ -66,8 +66,8 @@ ProcessingInstruction::~ProcessingInstruction()
     // crashes. We need to investigate ProcessingInstruction lifetime.
     if (inDocument() && m_isCSS)
         document().styleEngine().removeStyleSheetCandidateNode(this);
-#endif
     clearEventListenerForXSLT();
+#endif
 }
 
 EventListener* ProcessingInstruction::eventListenerForXSLT()
@@ -309,6 +309,7 @@ void ProcessingInstruction::clearSheet()
 DEFINE_TRACE(ProcessingInstruction)
 {
     visitor->trace(m_sheet);
+    visitor->trace(m_listenerForXSLT);
     CharacterData::trace(visitor);
 }