Oilpan: Reapply: Remove all the RefPtrs and most of the raw pointers to style

Source/core/dom/StyleElement.cpp

Index: Source/core/dom/StyleElement.cpp
diff --git a/Source/core/dom/StyleElement.cpp b/Source/core/dom/StyleElement.cpp
index 5d377b816b5e2a3e33d761d8afe4789a1ed7cb8a..acc26939e41d8178be73ba1f1068fe1f62e0d19a 100644
--- a/Source/core/dom/StyleElement.cpp
+++ b/Source/core/dom/StyleElement.cpp
@@ -76,7 +76,7 @@ void StyleElement::removedFromDocument(Document& document, Element* element, Con
     ASSERT(element);
     document.styleEngine()->removeStyleSheetCandidateNode(element, scopingNode, treeScope);
 
-    RefPtr<StyleSheet> removedSheet = m_sheet;
+    RefPtrWillBeRawPtr<StyleSheet> removedSheet = m_sheet.get();
 
     if (m_sheet)
         clearSheet(element);