Initial implementation of a SkColorSpace_A2B xform

src/core/SkColorSpaceXform_A2B.h

Index: src/core/SkColorSpaceXform_A2B.h
diff --git a/src/core/SkColorSpaceXform_A2B.h b/src/core/SkColorSpaceXform_A2B.h
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index 0000000000000000000000000000000000000000..84a3125a5ac95e7bdeaa2aabe1e6f7c76d777cd8
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+++ b/src/core/SkColorSpaceXform_A2B.h
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+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkColorSpaceXform_A2B_DEFINED
+#define SkColorSpaceXform_A2B_DEFINED
+
+#include "SkColorSpaceXform_Base.h"
+
+#include <memory>
+#include <vector>
+
+class SkColorSpace_A2B;
+class SkColorSpace_XYZ;
+enum SkGammaNamed : uint8_t;
+
+class SkColorSpaceXform_A2B : public SkColorSpaceXform_Base {
+public:
+    bool onApply(ColorFormat dstFormat, void* dst, ColorFormat srcFormat, const void* src,
+                 int count, SkAlphaType alphaType) const override;
+
+private:
+    SkColorSpaceXform_A2B(SkColorSpace_A2B* srcSpace, SkColorSpace_XYZ* dstSpace);
+
+    void concatTransforms();
+
+    class ProcessingElement;
+    class ApplyCLUT;
+    class LabToXYZ;
+    class ApplyMatrix;
+    class ApplyGammaSRGB;
+    class ApplyGamma2Dot2;
+    class ApplyGammaValue;
+    class ApplyGammaParams;
+    class ApplyGammaTable;
+
+    std::vector<std::unique_ptr<ProcessingElement>> fProcessingElements;
+    const uint8_t*                                  fDstGammaTables[3];
+    sk_sp<SkData>                                   fDstStorage;
+    SkGammaNamed                                    fDstGamma;
+
+    friend class SkColorSpaceXform;
+};
+
+#endif