Second small fragment from "Reduce dependence on GrSurface's origin field"

TBR=bsalomon@google.com
Change-Id: Ifcfe56b1117b64821b2bfc34ba36d120227d15fa
Reviewed-on: https://skia-review.googlesource.com/25802
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/tests/SRGBMipMapTest.cpp b/tests/SRGBMipMapTest.cpp
index 8d035e1..07332e4 100644
--- a/tests/SRGBMipMapTest.cpp
+++ b/tests/SRGBMipMapTest.cpp
@@ -124,6 +124,7 @@
     // Create our test texture
     GrSurfaceDesc desc;
     desc.fFlags = kNone_GrSurfaceFlags;
+    desc.fOrigin = kTopLeft_GrSurfaceOrigin;
     desc.fConfig = kSRGBA_8888_GrPixelConfig;
     desc.fWidth = texS;
     desc.fHeight = texS;