Delete unused AnimatableValue code

third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h

Index: third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h
diff --git a/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h b/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h
index 4aa772234abb0bb52064d1e41456dbaf0c124b54..e48a09365c45ae99f723c5bb9359cac5a259a2c1 100644
--- a/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h
+++ b/third_party/WebKit/Source/core/animation/animatable/AnimatableLengthSize.h
@@ -44,14 +44,6 @@ class AnimatableLengthSize final : public AnimatableValue {
     return adoptRef(
         new AnimatableLengthSize(std::move(width), std::move(height)));
   }
-  const AnimatableValue* width() const { return m_width.get(); }
-  const AnimatableValue* height() const { return m_height.get(); }
-
-  bool usesDefaultInterpolationWith(const AnimatableValue*) const override;
-
- protected:
-  PassRefPtr<AnimatableValue> interpolateTo(const AnimatableValue*,
-                                            double fraction) const override;
 
  private:
   AnimatableLengthSize(PassRefPtr<AnimatableValue> width,