Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/dom/DocumentMarkerController.h

Index: Source/core/dom/DocumentMarkerController.h
diff --git a/Source/core/dom/DocumentMarkerController.h b/Source/core/dom/DocumentMarkerController.h
index 658fe7c5b2ebde1f58aa7c084c6ca0c833dde71f..b57ffb5105c41f83b57db7c2d5cb5a3960306fff 100644
--- a/Source/core/dom/DocumentMarkerController.h
+++ b/Source/core/dom/DocumentMarkerController.h
@@ -28,6 +28,7 @@
 #define DocumentMarkerController_h
 
 #include "core/dom/DocumentMarker.h"
+#include "heap/Handle.h"
 #include "platform/geometry/IntRect.h"
 #include "wtf/HashMap.h"
 #include "wtf/Vector.h"
@@ -65,6 +66,8 @@ public:
     void removeMarkers(Range*, DocumentMarker::MarkerTypes = DocumentMarker::AllMarkers(), RemovePartiallyOverlappingMarkerOrNot = DoNotRemovePartiallyOverlappingMarker);
     void removeMarkers(Node*, unsigned startOffset, int length, DocumentMarker::MarkerTypes = DocumentMarker::AllMarkers(),  RemovePartiallyOverlappingMarkerOrNot = DoNotRemovePartiallyOverlappingMarker);
 
+    void clearWeakMembers(Visitor*);
+
     void removeMarkers(DocumentMarker::MarkerTypes = DocumentMarker::AllMarkers());
     void removeMarkers(Node*, DocumentMarker::MarkerTypes = DocumentMarker::AllMarkers());
     void repaintMarkers(DocumentMarker::MarkerTypes = DocumentMarker::AllMarkers());