WIP: Implement CSS transitions on top of InterpolationTypes instead of AnimatableValues

third_party/WebKit/Source/core/animation/InterpolationType.h

Index: third_party/WebKit/Source/core/animation/InterpolationType.h
diff --git a/third_party/WebKit/Source/core/animation/InterpolationType.h b/third_party/WebKit/Source/core/animation/InterpolationType.h
index f5f65bfd9066adf8ac1dcddb0e7a5adad8b1e6dd..5ebd1f2582b42ecb435957f2d45c7ed1f2d3b175 100644
--- a/third_party/WebKit/Source/core/animation/InterpolationType.h
+++ b/third_party/WebKit/Source/core/animation/InterpolationType.h
@@ -60,14 +60,24 @@ public:
         return maybeMergeSingles(std::move(start), std::move(end));
     }
 
+    virtual PairwiseInterpolationValue maybeMergeSingles(InterpolationValue&& start, InterpolationValue&& end) const
+    {
+        DCHECK(!start.nonInterpolableValue);
+        DCHECK(!end.nonInterpolableValue);
+        return PairwiseInterpolationValue(
+            std::move(start.interpolableValue),
+            std::move(end.interpolableValue),
+            nullptr);
+    }
+
     virtual InterpolationValue maybeConvertSingle(const PropertySpecificKeyframe&, const InterpolationEnvironment&, const InterpolationValue& underlying, ConversionCheckers&) const = 0;
 
     virtual InterpolationValue maybeConvertUnderlyingValue(const InterpolationEnvironment&) const = 0;
 
     virtual void composite(UnderlyingValueOwner& underlyingValueOwner, double underlyingFraction, const InterpolationValue& value, double interpolationFraction) const
     {
-        ASSERT(!underlyingValueOwner.value().nonInterpolableValue);
-        ASSERT(!value.nonInterpolableValue);
+        DCHECK(!underlyingValueOwner.value().nonInterpolableValue);
+        DCHECK(!value.nonInterpolableValue);
         underlyingValueOwner.mutableValue().interpolableValue->scaleAndAdd(underlyingFraction, *value.interpolableValue);
     }
 
@@ -82,16 +92,6 @@ protected:
         : m_property(property)
     { }
 
-    virtual PairwiseInterpolationValue maybeMergeSingles(InterpolationValue&& start, InterpolationValue&& end) const
-    {
-        ASSERT(!start.nonInterpolableValue);
-        ASSERT(!end.nonInterpolableValue);
-        return PairwiseInterpolationValue(
-            std::move(start.interpolableValue),
-            std::move(end.interpolableValue),
-            nullptr);
-    }
-
     const PropertyHandle m_property;
 };