Oilpan: Prepare moving AXObject to heap

Source/modules/accessibility/AXSpinButton.h

Index: Source/modules/accessibility/AXSpinButton.h
diff --git a/Source/modules/accessibility/AXSpinButton.h b/Source/modules/accessibility/AXSpinButton.h
index ce0a53694a7ef5115ffdc6bab5e848c76a7512bd..dbe57b727e0a7d720283071c48d661cbb16ef15b 100644
--- a/Source/modules/accessibility/AXSpinButton.h
+++ b/Source/modules/accessibility/AXSpinButton.h
@@ -36,8 +36,9 @@ class AXObjectCacheImpl;
 
 class AXSpinButton final : public AXMockObject {
 public:
-    static PassRefPtr<AXSpinButton> create(AXObjectCacheImpl*);
+    static PassRefPtrWillBeRawPtr<AXSpinButton> create(AXObjectCacheImpl*);
     virtual ~AXSpinButton();
+    DECLARE_VIRTUAL_TRACE();
 
     void setSpinButtonElement(SpinButtonElement* spinButton) { m_spinButtonElement = spinButton; }
     void step(int amount);
@@ -53,12 +54,12 @@ private:
     virtual void detach() override;
     virtual void detachFromParent() override;
 
-    SpinButtonElement* m_spinButtonElement;
+    RawPtrWillBeWeakMember<SpinButtonElement> m_spinButtonElement;
 };
 
 class AXSpinButtonPart final : public AXMockObject {
 public:
-    static PassRefPtr<AXSpinButtonPart> create(AXObjectCacheImpl*);
+    static PassRefPtrWillBeRawPtr<AXSpinButtonPart> create(AXObjectCacheImpl*);
     virtual ~AXSpinButtonPart() { }
 
     bool isIncrementor() const { return m_isIncrementor; }