Make flex-grow and flex-shrink interpolation continuous with 0

Source/core/animation/animatable/AnimatableDouble.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 22 matching lines @@
 
 #include "core/CoreExport.h"
 #include "core/animation/animatable/AnimatableValue.h"
 
 namespace blink {
 
 class CORE_EXPORT AnimatableDouble final : public AnimatableValue {
 public:
     ~AnimatableDouble() override { }
 
-    enum Constraint {
-        Unconstrained,
-        InterpolationIsNonContinuousWithZero,
-    };
-
-    static PassRefPtrWillBeRawPtr<AnimatableDouble> create(double number, Constraint constraint = Unconstrained)
+    static PassRefPtrWillBeRawPtr<AnimatableDouble> create(double number)
     {
-        return adoptRefWillBeNoop(new AnimatableDouble(number, constraint));
+        return adoptRefWillBeNoop(new AnimatableDouble(number));
     }
 
     double toDouble() const { return m_number; }
 
     DEFINE_INLINE_VIRTUAL_TRACE() { AnimatableValue::trace(visitor); }
 
 protected:
     PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const override;
-    bool usesDefaultInterpolationWith(const AnimatableValue*) const override;
 
 private:
-    AnimatableDouble(double number, Constraint constraint)
+    AnimatableDouble(double number)
         : m_number(number)
-        , m_constraint(constraint)
     {
     }
     AnimatableType type() const override { return TypeDouble; }
     bool equalTo(const AnimatableValue*) const override;
 
     double m_number;
-    Constraint m_constraint;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableDouble, isDouble());
 
 } // namespace blink
 
 #endif // AnimatableDouble_h