Add color gamut xform helpers to GrGLSLShaderBuilder

src/image/SkImageShader.cpp

Index: src/image/SkImageShader.cpp
diff --git a/src/image/SkImageShader.cpp b/src/image/SkImageShader.cpp
index db2bacb4ef4d96e9c2db5e02184c5463d1086d7a..9afd2073602fba7113436e14273fbfd226f6f4bd 100644
--- a/src/image/SkImageShader.cpp
+++ b/src/image/SkImageShader.cpp
@@ -214,11 +214,15 @@ sk_sp<GrFragmentProcessor> SkImageShader::asFragmentProcessor(const AsFPArgs& ar
         return nullptr;
     }
 
+    SkImageInfo info = as_IB(fImage)->onImageInfo();
+    sk_sp<GrColorSpaceXform> colorSpaceXform = GrColorSpaceXform::Make(info.colorSpace(),
+                                                                       args.fDstColorSpace,
+                                                                       info.alphaType());
     sk_sp<GrFragmentProcessor> inner;
     if (doBicubic) {
-        inner = GrBicubicEffect::Make(texture, nullptr, matrix, tm);
+        inner = GrBicubicEffect::Make(texture, std::move(colorSpaceXform), matrix, tm);
     } else {
-        inner = GrSimpleTextureEffect::Make(texture, nullptr, matrix, params);
+        inner = GrSimpleTextureEffect::Make(texture, std::move(colorSpaceXform), matrix, params);
     }
 
     if (GrPixelConfigIsAlphaOnly(texture->config())) {