Oilpan: move editing objects to the heap.

Source/core/editing/VisiblePosition.h

Index: Source/core/editing/VisiblePosition.h
diff --git a/Source/core/editing/VisiblePosition.h b/Source/core/editing/VisiblePosition.h
index f9f84cf02bbcba3d421a460e7e30350f6a2d7526..aa76c05b0458f1560a140eabf6e5adcc41bc0c6e 100644
--- a/Source/core/editing/VisiblePosition.h
+++ b/Source/core/editing/VisiblePosition.h
@@ -49,7 +49,8 @@ namespace WebCore {
 class InlineBox;
 class Node;
 
-class VisiblePosition {
+class VisiblePosition FINAL {
+    DISALLOW_ALLOCATION();
 public:
     // NOTE: UPSTREAM affinity will be used only if pos is at end of a wrapped line,
     // otherwise it will be converted to DOWNSTREAM
@@ -99,6 +100,8 @@ public:
     // FIXME: navigation with transforms should be smarter.
     int lineDirectionPointForBlockDirectionNavigation() const;
 
+    void trace(Visitor*);
+
 #ifndef NDEBUG
     void debugPosition(const char* msg = "") const;
     void formatForDebugger(char* buffer, unsigned length) const;