Add foundation for removing AnimatableValues from StyleInterpolation

Source/core/animation/InterpolationIsInvalid.h

Index: Source/core/animation/InterpolationIsInvalid.h
diff --git a/Source/core/animation/InterpolationIsInvalid.h b/Source/core/animation/InterpolationIsInvalid.h
new file mode 100644
index 0000000000000000000000000000000000000000..af13d4e709e12c50c638438520ecfd23d0e79e36
--- /dev/null
+++ b/Source/core/animation/InterpolationIsInvalid.h
@@ -0,0 +1,56 @@
+// 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 InterpolationIsInvalid_h
+#define InterpolationIsInvalid_h
+
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class StyleResolverState;
+
+class InterpolationIsInvalid : public RefCountedWillBeGarbageCollectedFinalized<InterpolationIsInvalid> {
+public:
+    virtual ~InterpolationIsInvalid() { }
+
+    bool checkChain(const StyleResolverState& state)
+    {
+        return checkSingle(state) || (m_next && m_next->checkChain(state));
+    }
+
+    static void chain(RefPtrWillBeRawPtr<InterpolationIsInvalid>& existing, PassRefPtrWillBeRawPtr<InterpolationIsInvalid> extra)

[Eric Willigers, 2015/05/27 04:26:35]

Possibly rename arguments to  prefix, suffix

[alancutter (OOO until 2018), 2015/05/27 08:27:48]

Done.

+    {
+        if (!extra)
+            return;
+        if (!existing)
+            existing = extra;
+        else if (existing != extra)
+            existing->chainWith(extra);
+    }
+
+    DEFINE_INLINE_VIRTUAL_TRACE()
+    {
+        visitor->trace(m_next);
+    }
+
+protected:
+    virtual bool checkSingle(const StyleResolverState&) = 0;
+
+private:
+    void chainWith(PassRefPtrWillBeRawPtr<InterpolationIsInvalid> extra)

[Eric Willigers, 2015/05/27 04:26:35]

Possibly rename argument to  suffix

[alancutter (OOO until 2018), 2015/05/27 08:27:48]

Done.

+    {
+        ASSERT(extra);
+        if (!m_next)
+            m_next = extra;
+        else if (m_next != extra)
+            m_next->chainWith(extra);

[Eric Willigers, 2015/05/27 04:26:35]

Explicit while loop instead?

[alancutter (OOO until 2018), 2015/05/27 08:27:48]

Done.

+    }
+
+    RefPtrWillBeMember<InterpolationIsInvalid> m_next;
+};
+
+} // namespace blink
+
+#endif // InterpolationIsInvalid_h