Tighten up SkSpecialSurface factory functions

tests/ImageFilterTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkCanvas.h"
@@ skipping 352 matching lines @@
 static sk_sp<SkImageFilter> make_blue(sk_sp<SkImageFilter> input,
                                       const SkImageFilter::CropRect* cropRect) {
     sk_sp<SkColorFilter> filter(SkColorFilter::MakeModeFilter(SK_ColorBLUE,
                                                               SkXfermode::kSrcIn_Mode));
     return SkColorFilterImageFilter::Make(std::move(filter), std::move(input), cropRect);
 }
 
 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
     {
         const SkImageInfo info = SkImageInfo::MakeN32(widthHeight, widthHeight,
                                                       kOpaque_SkAlphaType);
         return SkSpecialSurface::MakeRaster(info);
     }
 }
 
 static sk_sp<SkSpecialImage> create_empty_special_image(GrContext* context, int widthHeight) {
@@ skipping 1345 matching lines @@
         { SkColorFilterImageFilter::Make(cf, blif), false },
         { SkMergeImageFilter::Make(cfif, blif),     false },
         { SkComposeImageFilter::Make(blif, cfif),   false },
     };
     
     for (const auto& rec : recs) {
         const bool canHandle = rec.fFilter->canHandleComplexCTM();
         REPORTER_ASSERT(reporter, canHandle == rec.fExpectCanHandle);
     }
 }