Refactored SkColorSpace and added in a Lab PCS GM

src/gpu/GrColorSpaceXform.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrColorSpaceXform.h"
 #include "SkColorSpace.h"
 #include "SkColorSpace_Base.h"
+#include "SkColorSpace_XYZTRC.h"
 #include "SkMatrix44.h"
 
 static inline bool sk_float_almost_equals(float x, float y, float tol) {
     return sk_float_abs(x - y) <= tol;
 }
 
 static inline bool matrix_is_almost_identity(const SkMatrix44& m,
                                              SkMScalar tol = SK_MScalar1 / (1 << 12)) {
     return
         sk_float_almost_equals(m.getFloat(0, 0), 1.0f, tol) &&
@@ skipping 22 matching lines @@
         // Invalid
         return nullptr;
     }
 
     if (src == dst) {
         // Quick equality check - no conversion needed in this case
         return nullptr;
     }
 
     SkMatrix44 srcToDst(SkMatrix44::kUninitialized_Constructor);
-    srcToDst.setConcat(as_CSB(dst)->fromXYZD50(), as_CSB(src)->toXYZD50());
+    srcToDst.setConcat(as_CSXYZ(dst)->fromXYZD50(), as_CSXYZ(src)->toXYZD50());

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

Can we expose these functions on SkColorSpace_Base?

virtual SkMatrix44* toXYZD50() const;
or
virtual bool toXYZD50(SkMatrix44* toXYZD50);

And then we assert that they return success here?

 
     if (matrix_is_almost_identity(srcToDst)) {
         return nullptr;
     }
 
     return sk_make_sp<GrColorSpaceXform>(srcToDst);
 }
 
 bool GrColorSpaceXform::Equals(const GrColorSpaceXform* a, const GrColorSpaceXform* b) {
     if (a == b) {
         return true;
     }
 
     if (!a || !b) {
         return false;
     }
 
     return a->fSrcToDst == b->fSrcToDst;
 }
 
 GrColor4f GrColorSpaceXform::apply(const GrColor4f& srcColor) {
     GrColor4f result;
     fSrcToDst.mapScalars(srcColor.fRGBA, result.fRGBA);
     return result;
 }