Hide (mostly) unused SkColorSpace writeToICC() function

src/core/SkColorSpace_Base.h

Index: src/core/SkColorSpace_Base.h
diff --git a/src/core/SkColorSpace_Base.h b/src/core/SkColorSpace_Base.h
index f4507732b5eaf8b623b270441e0d859bce8d75cc..3a2518db9c176e7e4ea0e68c39a005f625370f1b 100644
--- a/src/core/SkColorSpace_Base.h
+++ b/src/core/SkColorSpace_Base.h
@@ -180,13 +180,17 @@ public:
 
     const SkColorLookUpTable* colorLUT() const { return fColorLUT.get(); }
 
+private:
+
     /**
-     *  Writes this object as an ICC profile.
+     *  FIXME (msarett):
+     *  Hiding this function until we can determine if we need it.  Known issues include:
+     *  Only writes 3x3 matrices
+     *  Only writes float gammas
+     *  Rejected by some parsers because the "profile description" is empty
      */
     sk_sp<SkData> writeToICC() const;
 
-private:
-
     static sk_sp<SkColorSpace> NewRGB(GammaNamed gammaNamed, const SkMatrix44& toXYZD50);
 
     SkColorSpace_Base(GammaNamed gammaNamed, const SkMatrix44& toXYZ, Named named);
@@ -200,6 +204,7 @@ private:
 
     friend class SkColorSpace;
     friend class ColorSpaceXformTest;
+    friend class ColorSpaceTest;
     typedef SkColorSpace INHERITED;
 };