Implement left property animation on InvalidatableStyleInterpolation

Source/core/animation/InterpolableValue.h

Index: Source/core/animation/InterpolableValue.h
diff --git a/Source/core/animation/InterpolableValue.h b/Source/core/animation/InterpolableValue.h
index 0b6040841c1e767dcf6bd76c4de15bbe4947b842..fe33304b895aa31d26c38526dc857c8b0a5e5ff9 100644
--- a/Source/core/animation/InterpolableValue.h
+++ b/Source/core/animation/InterpolableValue.h
@@ -28,11 +28,11 @@ public:
 
 private:
     virtual void interpolate(const InterpolableValue& to, const double progress, InterpolableValue& result) const = 0;
-    virtual void add(const InterpolableValue& rhs, InterpolableValue& result) const = 0;
-    virtual void multiply(double scalar, InterpolableValue& result) const = 0;
+    virtual void scaleAndAdd(double scale, const InterpolableValue& other) = 0;
 
     friend class Interpolation;
     friend class PairwisePrimitiveInterpolation;
+    friend class InvalidatableStyleInterpolation;
 
     // Keep interpolate private, but allow calls within the hierarchy without
     // knowledge of type.
@@ -57,8 +57,7 @@ public:
 
 private:
     virtual void interpolate(const InterpolableValue& to, const double progress, InterpolableValue& result) const override final;
-    virtual void add(const InterpolableValue& rhs, InterpolableValue& result) const override final;
-    virtual void multiply(double scalar, InterpolableValue& result) const override final;
+    virtual void scaleAndAdd(double scale, const InterpolableValue& other) override final;
     double m_value;
 
     explicit InterpolableNumber(double value)
@@ -81,8 +80,7 @@ public:
 
 private:
     virtual void interpolate(const InterpolableValue& to, const double progress, InterpolableValue& result) const override final;
-    virtual void add(const InterpolableValue& rhs, InterpolableValue& result) const override final;
-    virtual void multiply(double scalar, InterpolableValue& result) const override final { ASSERT_NOT_REACHED(); }
+    virtual void scaleAndAdd(double scale, const InterpolableValue& other) override final { ASSERT_NOT_REACHED(); }
     bool m_value;
 
     explicit InterpolableBool(bool value)
@@ -123,6 +121,11 @@ public:
         ASSERT(position < m_size);
         return m_values[position].get();
     }
+    InterpolableValue* get(size_t position)
+    {
+        ASSERT(position < m_size);
+        return m_values[position].get();
+    }
     size_t length() const { return m_size; }
     virtual PassOwnPtrWillBeRawPtr<InterpolableValue> clone() const override final { return create(*this); }
 
@@ -130,8 +133,7 @@ public:
 
 private:
     virtual void interpolate(const InterpolableValue& to, const double progress, InterpolableValue& result) const override final;
-    virtual void add(const InterpolableValue& rhs, InterpolableValue& result) const override final;
-    virtual void multiply(double scalar, InterpolableValue& result) const override final;
+    virtual void scaleAndAdd(double scale, const InterpolableValue& other) override final;
     explicit InterpolableList(size_t size)
         : m_size(size)
         , m_values(m_size)
@@ -166,8 +168,7 @@ public:
 
 private:
     virtual void interpolate(const InterpolableValue &to, const double progress, InterpolableValue& result) const override final;
-    virtual void add(const InterpolableValue& rhs, InterpolableValue& result) const override final { ASSERT_NOT_REACHED(); }
-    virtual void multiply(double scalar, InterpolableValue& result) const override final { ASSERT_NOT_REACHED(); }
+    virtual void scaleAndAdd(double scale, const InterpolableValue& other) override final { ASSERT_NOT_REACHED(); }
     RefPtrWillBeMember<AnimatableValue> m_value;
 
     InterpolableAnimatableValue(PassRefPtrWillBeRawPtr<AnimatableValue> value)