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

Source/core/dom/StyleSheetCollection.cpp

Index: Source/core/dom/StyleSheetCollection.cpp
diff --git a/Source/core/dom/StyleSheetCollection.cpp b/Source/core/dom/StyleSheetCollection.cpp
index 9187d67cf0b0cafb520fb161ddb145eceef0c9af..186f1a499a691bc1f2792dcbeeabdce4e6fa7107 100644
--- a/Source/core/dom/StyleSheetCollection.cpp
+++ b/Source/core/dom/StyleSheetCollection.cpp
@@ -52,7 +52,7 @@ void StyleSheetCollection::swapSheetsForSheetList(WillBeHeapVector<RefPtrWillBeM
     m_styleSheetsForStyleSheetList.swap(sheets);
 }
 
-void StyleSheetCollection::appendActiveStyleSheets(const WillBePersistentHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& sheets)
+void StyleSheetCollection::appendActiveStyleSheets(const WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& sheets)
 {
     m_activeAuthorStyleSheets.appendVector(sheets);
 }
@@ -67,4 +67,10 @@ void StyleSheetCollection::appendSheetForList(StyleSheet* sheet)
     m_styleSheetsForStyleSheetList.append(sheet);
 }
 
+void StyleSheetCollection::trace(Visitor* visitor)
+{
+    visitor->trace(m_activeAuthorStyleSheets);
+    visitor->trace(m_styleSheetsForStyleSheetList);
+}
+
 }