Add foundation for removing AnimatableValues from StyleInterpolation

Source/core/animation/AnimationType.h

Index: Source/core/animation/AnimationType.h
diff --git a/Source/core/animation/AnimationType.h b/Source/core/animation/AnimationType.h
new file mode 100644
index 0000000000000000000000000000000000000000..1e0e7bcd28b3387d02d3a373f8e6bcf47aa4942f
--- /dev/null
+++ b/Source/core/animation/AnimationType.h
@@ -0,0 +1,64 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef AnimationType_h
+#define AnimationType_h
+
+#include "core/animation/InterpolableValue.h"
+#include "core/animation/InterpolationPrimitive.h"
+#include "core/animation/NonInterpolableValue.h"
+#include "core/animation/StringKeyframe.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class StyleResolverState;
+
+// A singleton class that provides functions for:

[shans, 2015/06/22 11:43:21]

We already know this is a class which provides functions, no need to tell us
again.

[alancutter (OOO until 2018), 2015/06/23 05:05:33]

Done.

+// - Converting from animation keyframe(s) to interpolation compatible representations.
+// - Applying interpolation compatible representations of values to a StyleResolverState.

[shans, 2015/06/22 11:43:21]

Reference the functions that do these two things.

[alancutter (OOO until 2018), 2015/06/23 05:05:33]

Done.

+class AnimationType {
+public:
+    CSSPropertyID property() const { return m_property; }
+
+    // Represents logic for determining whether a conversion decision is no longer valid given the current environment.
+    class ConversionInvalidator : public NoBaseWillBeGarbageCollectedFinalized<ConversionInvalidator> {
+    public:
+        virtual ~ConversionInvalidator() { }
+        virtual bool isInvalid(const StyleResolverState&) const = 0;
+        DEFINE_INLINE_VIRTUAL_TRACE() { }
+    };
+    using ConversionInvalidators = WillBeHeapVector<OwnPtrWillBeMember<ConversionInvalidator>>;
+
+    virtual PassOwnPtrWillBeRawPtr<PairwiseInterpolationPrimitive> maybeConvertPairwise(const CSSPropertySpecificKeyframe& startKeyframe, const CSSPropertySpecificKeyframe& endKeyframe, const StyleResolverState*, ConversionInvalidators&) const
+    {
+        return nullptr;
+    }
+
+    PassOwnPtrWillBeRawPtr<FlipInterpolationPrimitive::Side> maybeConvertSingle(const CSSPropertySpecificKeyframe& keyframe, const StyleResolverState* state, ConversionInvalidators& conversionInvalidators) const
+    {
+        OwnPtrWillBeRawPtr<FlipInterpolationPrimitive::Side> result = maybeConvertSingleImpl(keyframe, state, conversionInvalidators);
+        if (result)
+            result->type = this;
+        return result.release();
+    }

[shans, 2015/06/22 11:43:21]

nit: it's probably better just to result->type = this; in each subclass. Adding
an impl method seems really heavyweight in comparison.

[alancutter (OOO until 2018), 2015/06/23 05:05:33]

Done.

+
+    virtual void apply(const InterpolableValue&, const NonInterpolableValue*, StyleResolverState&) const = 0;
+
+protected:
+    AnimationType(CSSPropertyID property)
+        : m_property(property)
+    { }
+
+    virtual PassOwnPtrWillBeRawPtr<FlipInterpolationPrimitive::Side> maybeConvertSingleImpl(const CSSPropertySpecificKeyframe&, const StyleResolverState*, ConversionInvalidators&) const
+    {
+        return nullptr;
+    }
+
+    const CSSPropertyID m_property;
+};
+
+} // namespace blink
+
+#endif // AnimationType_h