Add support for the Rec601 YUV color space to GrYUVtoRGBEffect.

gm/yuvtorgbeffect.cpp

Index: gm/yuvtorgbeffect.cpp
diff --git a/gm/yuvtorgbeffect.cpp b/gm/yuvtorgbeffect.cpp
index 12676f262e2477f72cd3a19487ea2b7400e3a0fd..2ac39be8a293cbcafba7705f49a29453cfadd27e 100644
--- a/gm/yuvtorgbeffect.cpp
+++ b/gm/yuvtorgbeffect.cpp
@@ -107,7 +107,8 @@ protected:
             SkAutoTUnref<GrEffect> effect(
                         GrYUVtoRGBEffect::Create(texture[indices[i][0]],
                                                  texture[indices[i][1]],
-                                                 texture[indices[i][2]]));
+                                                 texture[indices[i][2]],
+                                                 GrYUVtoRGBEffect::kJPEG));
             if (effect) {
                 SkMatrix viewMatrix;
                 viewMatrix.setTranslate(x, y);