Refactored SkColorSpace and added in a Lab PCS GM

src/core/SkColorSpace_XYZTRC.h

Index: src/core/SkColorSpace_XYZTRC.h
diff --git a/src/core/SkColorSpace_XYZTRC.h b/src/core/SkColorSpace_XYZTRC.h
new file mode 100644
index 0000000000000000000000000000000000000000..2000a3cc384a5645518f03a615b2fb4c997d7866
--- /dev/null
+++ b/src/core/SkColorSpace_XYZTRC.h
@@ -0,0 +1,60 @@
+/*
+ * 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 SkColorSpace_XYZTRC_DEFINED
+#define SkColorSpace_XYZTRC_DEFINED
+
+#include "SkColorSpace_Base.h"
+#include "SkData.h"
+#include "SkOnce.h"
+
+class SkColorSpace_XYZTRC : public SkColorSpace_Base {
+public:
+    SkGammaNamed gammaNamed() const { return fGammaNamed; }
+    
+    const SkGammas* gammas() const { return fGammas.get(); }
+    
+    const SkMatrix44& toXYZD50() const { return fToXYZD50; }
+
+    const SkMatrix44& fromXYZD50() const;
+
+private:
+    SkColorSpace_XYZTRC(SkGammaNamed gammaNamed, const SkMatrix44& toXYZ);
+
+    SkColorSpace_XYZTRC(SkGammaNamed gammaNamed, sk_sp<SkGammas> gammas,
+                        const SkMatrix44& toXYZ, sk_sp<SkData> profileData);
+
+    const SkGammaNamed        fGammaNamed;
+    sk_sp<SkGammas>           fGammas;
+    sk_sp<SkData>             fProfileData;

[msarett, 2016/10/05 19:05:53]

nit: This field is already on the base.

+    const SkMatrix44          fToXYZD50;
+    
+    mutable SkMatrix44        fFromXYZD50;
+    mutable SkOnce            fFromXYZOnce;
+
+    friend class SkColorSpace;
+    friend class SkColorSpace_Base;
+    friend class ColorSpaceXformTest;
+    typedef SkColorSpace_Base INHERITED;
+};
+
+inline SkColorSpace_XYZTRC* as_CSXYZ(SkColorSpace* colorSpace) {

[msarett, 2016/10/05 19:05:53]

These casts are convenient in SkColorSpace_Base because we know that every
SkColorSpace is actually a SkColorSpace_Base.

In this case, where we might not know, they seem dangerous to me.

+    SkASSERT(as_CSB(colorSpace)->type() == SkColorSpace_Base::Type::kXYZTRC);
+    return static_cast<SkColorSpace_XYZTRC*>(colorSpace);
+}
+
+inline const SkColorSpace_XYZTRC* as_CSXYZ(const SkColorSpace* colorSpace) {
+    SkASSERT(as_CSB(colorSpace)->type() == SkColorSpace_Base::Type::kXYZTRC);
+    return static_cast<const SkColorSpace_XYZTRC*>(colorSpace);
+}
+
+inline SkColorSpace_XYZTRC* as_CSXYZ(const sk_sp<SkColorSpace>& colorSpace) {
+    SkASSERT(as_CSB(colorSpace)->type() == SkColorSpace_Base::Type::kXYZTRC);
+    return static_cast<SkColorSpace_XYZTRC*>(colorSpace.get());
+}
+
+#endif