return 4x4 matrix from SkColorSpace

src/codec/SkPngCodec.cpp

Index: src/codec/SkPngCodec.cpp
diff --git a/src/codec/SkPngCodec.cpp b/src/codec/SkPngCodec.cpp
index 1ad7f8006ee85a0a8016e129dd15104993fe8108..55b3238ef4d5d69fcdb2bfe5ec09a489f4b1e750 100644
--- a/src/codec/SkPngCodec.cpp
+++ b/src/codec/SkPngCodec.cpp
@@ -208,7 +208,7 @@ sk_sp<SkColorSpace> read_color_space(png_structp png_ptr, png_infop info_ptr) {
 
     // Next, check for chromaticities.
     png_fixed_point XYZ[9];
-    SkFloat3x3 toXYZD50;
+    float toXYZD50[9];
     png_fixed_point gamma;
     SkFloat3 gammas;
     if (png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &XYZ[0], &XYZ[1], &XYZ[2], &XYZ[3], &XYZ[4],
@@ -221,7 +221,7 @@ sk_sp<SkColorSpace> read_color_space(png_structp png_ptr, png_infop info_ptr) {
         //                  we should add a new constructor to SkColorSpace that accepts
         //                  XYZ with D-Unkown?
         for (int i = 0; i < 9; i++) {
-            toXYZD50.fMat[i] = png_fixed_point_to_float(XYZ[i]);
+            toXYZD50[i] = png_fixed_point_to_float(XYZ[i]);
         }
 
         if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) {
@@ -233,8 +233,9 @@ sk_sp<SkColorSpace> read_color_space(png_structp png_ptr, png_infop info_ptr) {
             gammas.fVec[0] = gammas.fVec[1] = gammas.fVec[2] = 1.0f;
         }
 
-
-        return SkColorSpace::NewRGB(toXYZD50, gammas);
+        SkMatrix44 mat(SkMatrix44::kUninitialized_Constructor);
+        mat.set3x3ColMajorf(toXYZD50);
+        return SkColorSpace::NewRGB(mat, gammas);
     }
 
     // Last, check for gamma.
@@ -242,14 +243,11 @@ sk_sp<SkColorSpace> read_color_space(png_structp png_ptr, png_infop info_ptr) {
 
         // Guess a default value for cHRM?  Or should we just give up?
         // Here we use the identity matrix as a default.
-        // FIXME (msarett): Should SkFloat3x3 have a method to set the identity matrix?
-        memset(toXYZD50.fMat, 0, 9 * sizeof(float));
-        toXYZD50.fMat[0] = toXYZD50.fMat[4] = toXYZD50.fMat[8] = 1.0f;
 
         // Set the gammas.
         gammas.fVec[0] = gammas.fVec[1] = gammas.fVec[2] = png_inverted_fixed_point_to_float(gamma);
 
-        return SkColorSpace::NewRGB(toXYZD50, gammas);
+        return SkColorSpace::NewRGB(SkMatrix44::I(), gammas);
     }
 
 #endif // LIBPNG >= 1.6