Tighten up SkSpecialSurface factory functions

tests/ImageFilterTest.cpp

Index: tests/ImageFilterTest.cpp
diff --git a/tests/ImageFilterTest.cpp b/tests/ImageFilterTest.cpp
index 54e9a60007e90f4658a601f6c1e016cffc4bb2a6..56b3aaf5cdf6c26be8dab06b7e78c780e0aaeb9a 100644
--- a/tests/ImageFilterTest.cpp
+++ b/tests/ImageFilterTest.cpp
@@ -370,12 +370,9 @@ static sk_sp<SkImageFilter> make_blue(sk_sp<SkImageFilter> input,
 static sk_sp<SkSpecialSurface> create_empty_special_surface(GrContext* context, int widthHeight) {
 #if SK_SUPPORT_GPU
     if (context) {
-        GrSurfaceDesc desc;
-        desc.fConfig = kSkia8888_GrPixelConfig;
-        desc.fFlags  = kRenderTarget_GrSurfaceFlag;
-        desc.fWidth  = widthHeight;
-        desc.fHeight = widthHeight;
-        return SkSpecialSurface::MakeRenderTarget(context, desc);
+        return SkSpecialSurface::MakeRenderTarget(context,
+                                                  widthHeight, widthHeight,
+                                                  kSkia8888_GrPixelConfig);
     } else
 #endif
     {