Oilpan: fix build after r191432 (5bc98fff).

Source/core/animation/animatable/AnimatableLength.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 26 matching lines @@
 namespace blink {
 
 class AnimatableLength final : public AnimatableValue {
 public:
     static PassRefPtrWillBeRawPtr<AnimatableLength> create(const Length& length, float zoom)
     {
         return adoptRefWillBeNoop(new AnimatableLength(length, zoom));
     }
     Length length(float zoom, ValueRange) const;
 
+    DEFINE_INLINE_VIRTUAL_TRACE() { AnimatableValue::trace(visitor); }
+
 protected:
     virtual PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const override;
 
 private:
     static PassRefPtrWillBeRawPtr<AnimatableLength> create(double pixels, double percent, bool hasPixels, bool hasPercent)
     {
         return adoptRefWillBeNoop(new AnimatableLength(pixels, percent, hasPixels, hasPercent));
     }
     AnimatableLength(const Length&, float zoom);
     AnimatableLength(double pixels, double percent, bool hasPixels, bool hasPercent)
         : m_pixels(pixels)
         , m_percent(percent)
         , m_hasPixels(hasPixels)
         , m_hasPercent(hasPercent)
     {
         ASSERT(m_hasPixels || m_hasPercent);
     }
     virtual AnimatableType type() const override { return TypeLength; }
     virtual bool equalTo(const AnimatableValue*) const override;
 
-    DEFINE_INLINE_VIRTUAL_TRACE() { AnimatableValue::trace(visitor); }
-
     double m_pixels;
     double m_percent;
     bool m_hasPixels;
     bool m_hasPercent;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableLength, isLength());
 
 } // namespace blink
 
 #endif // AnimatableLength_h