Differentiate between sRGBGamma and 2Dot2Gamma

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2067833003

Review-Url: https://codereview.chromium.org/2067833003
diff --git a/gm/color4f.cpp b/gm/color4f.cpp
index ffe9a87..33d8377 100644
--- a/gm/color4f.cpp
+++ b/gm/color4f.cpp
@@ -95,8 +95,6 @@
     // red -> blue, green -> red, blue -> green
     mat.set3x3(0, 1, 0, 0, 0, 1, 1, 0, 0);
 
-    float linearGamma[3] = { 1.0f, 1.0f, 1.0f };
-
     const SkColor4f colors[] {
         { 1, 1, 0, 0 },
         { 1, 0, 1, 0 },
@@ -111,7 +109,8 @@
         sk_sp<SkShader> shaders[] {
             SkShader::MakeColorShader(c4, nullptr),
             SkShader::MakeColorShader(c4, SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named)),
-            SkShader::MakeColorShader(c4, SkColorSpace::NewRGB(linearGamma, mat)),
+            SkShader::MakeColorShader(c4, SkColorSpace::NewRGB(SkColorSpace::kLinear_GammaNamed,
+                                                               mat)),
         };
 
         canvas->save();