Oilpan: fix build after r193519.

Source/core/dom/Position.h

Index: Source/core/dom/Position.h
diff --git a/Source/core/dom/Position.h b/Source/core/dom/Position.h
index 397bd24cb9621b7a99462824ed85ba36c568ee91..02f95341a377746f02bd828dd19eef9fd4e21240 100644
--- a/Source/core/dom/Position.h
+++ b/Source/core/dom/Position.h
@@ -31,6 +31,7 @@
 #include "core/editing/EditingBoundary.h"
 #include "core/editing/EditingStrategy.h"
 #include "core/editing/TextAffinity.h"
+#include "platform/heap/Handle.h"
 #include "platform/text/TextDirection.h"
 #include "wtf/Assertions.h"
 #include "wtf/PassRefPtr.h"
@@ -232,6 +233,11 @@ public:
     void showTreeForThis() const;
 #endif
 
+    DEFINE_INLINE_TRACE()
+    {
+        visitor->trace(m_anchorNode);
+    }
+
 protected:
     PositionAlgorithm(const PositionAlgorithm&);
 
@@ -274,8 +280,6 @@ public:
 
     int compareTo(const Position&) const;
 
-    DECLARE_TRACE();
-
 #ifndef NDEBUG
     Node* nodeAsSelectionStart() const;
     Node* nodeAsSelectionEnd() const;