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

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

Index: third_party/WebKit/Source/core/animation/EffectModel.h
diff --git a/third_party/WebKit/Source/core/animation/EffectModel.h b/third_party/WebKit/Source/core/animation/EffectModel.h
index cdf0cb6d54c5cb0fcac41e396aee596159902a61..86c58b93bf77fce98f4758c720045ea9c1b6831e 100644
--- a/third_party/WebKit/Source/core/animation/EffectModel.h
+++ b/third_party/WebKit/Source/core/animation/EffectModel.h
@@ -34,6 +34,7 @@
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/CSSPropertyNames.h"
 #include "core/CoreExport.h"
+#include "core/animation/AnimationEffect.h"
 #include "core/animation/PropertyHandle.h"
 #include "platform/heap/Handle.h"
 #include "wtf/HashMap.h"
@@ -52,15 +53,49 @@ public:
         CompositeAdd,
     };
 
-    EffectModel() { }
     virtual ~EffectModel() { }
-    virtual bool sample(int iteration, double fraction, double iterationDuration, Vector<RefPtr<Interpolation>>&) const = 0;
 
-    virtual bool affects(PropertyHandle) const { return false; }
-    virtual bool isTransformRelatedEffect() const { return false; }
+    bool sample(int iteration, double fraction, double iterationDuration, Vector<RefPtr<Interpolation>>& result) const
+    {
+        DCHECK_GE(iteration, 0);
+        DCHECK(!isNull(fraction));
+        bool changed = iteration != m_lastIteration || fraction != m_lastFraction || iterationDuration != m_lastIterationDuration;
+        m_lastIteration = iteration;
+        m_lastFraction = fraction;
+        m_lastIterationDuration = iterationDuration;
+        sampleImpl(iteration, fraction, iterationDuration, result);
+        return changed;
+    }
+
+    virtual bool affects(PropertyHandle) const = 0;
+    bool isTransformRelatedEffect() const
+    {
+        return affects(PropertyHandle(CSSPropertyTransform))
+            || affects(PropertyHandle(CSSPropertyRotate))
+            || affects(PropertyHandle(CSSPropertyScale))
+            || affects(PropertyHandle(CSSPropertyTranslate));
+    }
+
     virtual bool isKeyframeEffectModel() const { return false; }
+    virtual bool isTransitionEffectModel() const { return false; }
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
+
+protected:
+    EffectModel()
+        : m_lastIteration(0)
+        , m_lastFraction(nullValue())
+        , m_lastIterationDuration(0)
+    { }
+
+    virtual void sampleImpl(int iteration, double fraction, double iterationDuration, Vector<RefPtr<Interpolation>>&) const = 0;
+
+    void clearLastFraction() const { m_lastFraction = nullValue(); }
+
+private:
+    mutable int m_lastIteration;
+    mutable double m_lastFraction;
+    mutable double m_lastIterationDuration;
 };
 
 } // namespace blink