Refactored SkColorSpace and added in a Lab PCS GM

src/gpu/GrColorSpaceXform.cpp

Index: src/gpu/GrColorSpaceXform.cpp
diff --git a/src/gpu/GrColorSpaceXform.cpp b/src/gpu/GrColorSpaceXform.cpp
index d2270fafdd4a2458b4f8a1721be0a4f41f5adf26..5d93bca4bda6c5436d22ea34a1b94b6a418a630d 100644
--- a/src/gpu/GrColorSpaceXform.cpp
+++ b/src/gpu/GrColorSpaceXform.cpp
@@ -8,6 +8,7 @@
 #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) {
@@ -50,7 +51,7 @@ sk_sp<GrColorSpaceXform> GrColorSpaceXform::Make(SkColorSpace* src, SkColorSpace
     }
 
     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;