Remove more oilpan.

sky/engine/core/html/canvas/HitRegion.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef HitRegion_h
 #define HitRegion_h
 
 #include "bindings/core/v8/Dictionary.h"
 #include "core/dom/Element.h"
 #include "platform/graphics/Path.h"
@@ skipping 39 matching lines @@
 
 private:
     explicit HitRegion(const HitRegionOptions&);
 
     String m_id;
     RefPtr<Element> m_control;
     Path m_path;
     WindRule m_fillRule;
 };
 
-class HitRegionManager final : public DummyBase<HitRegionManager> {
+class HitRegionManager final {
     WTF_MAKE_NONCOPYABLE(HitRegionManager);
     DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(HitRegionManager)
 public:
     static PassOwnPtr<HitRegionManager> create() { return adoptPtr(new HitRegionManager()); }
 
     void addHitRegion(PassRefPtr<HitRegion>);
 
     void removeHitRegion(HitRegion*);
     void removeHitRegionById(const String& id);
     void removeHitRegionByControl(Element*);
@@ skipping 17 matching lines @@
     typedef HashMap<RefPtr<Element>, RefPtr<HitRegion> > HitRegionControlMap;
 
     HitRegionList m_hitRegionList;
     HitRegionIdMap m_hitRegionIdMap;
     HitRegionControlMap m_hitRegionControlMap;
 };
 
 } // namespace blink
 
 #endif