factories should return baseclass, allowing the impl to specialize

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 "SkBitmapDevice.h"
 #include "SkBlurImageFilter.h"
@@ skipping 336 matching lines @@
     );
     SkPaint paint;
     paint.setShader(shader);
     canvas.drawCircle(x, y, radius, paint);
     return bitmap;
 }
 
 static void test_negative_blur_sigma(SkImageFilter::Proxy* proxy, skiatest::Reporter* reporter) {
     // Check that SkBlurImageFilter will accept a negative sigma, either in
     // the given arguments or after CTM application.
-    int width = 32, height = 32;
-    SkScalar five = SkIntToScalar(5);
+    const int width = 32, height = 32;
+    const SkScalar five = SkIntToScalar(5);
 
-    SkAutoTUnref<SkBlurImageFilter> positiveFilter(
-        SkBlurImageFilter::Create(five, five)
-    );
-
-    SkAutoTUnref<SkBlurImageFilter> negativeFilter(
-        SkBlurImageFilter::Create(-five, five)
-    );
+    SkAutoTUnref<SkImageFilter> positiveFilter(SkBlurImageFilter::Create(five, five));
+    SkAutoTUnref<SkImageFilter> negativeFilter(SkBlurImageFilter::Create(-five, five));
 
     SkBitmap gradient = make_gradient_circle(width, height);
     SkBitmap positiveResult1, negativeResult1;
     SkBitmap positiveResult2, negativeResult2;
     SkIPoint offset;
     SkImageFilter::Context ctx(SkMatrix::I(), SkIRect::MakeLargest(), nullptr);
     positiveFilter->filterImage(proxy, gradient, ctx, &positiveResult1, &offset);
     negativeFilter->filterImage(proxy, gradient, ctx, &negativeResult1, &offset);
     SkMatrix negativeScale;
     negativeScale.setScale(-SK_Scalar1, SK_Scalar1);
@@ skipping 38 matching lines @@
     // match the same filters drawn with a single full-canvas bitmap draw.
     // Tests pass by not asserting.
 
     SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(SK_ColorRED, SkXfermode::kSrcIn_Mode));
     SkPoint3 location = SkPoint3::Make(0, 0, SK_Scalar1);
     SkScalar kernel[9] = {
         SkIntToScalar( 1), SkIntToScalar( 1), SkIntToScalar( 1),
         SkIntToScalar( 1), SkIntToScalar(-7), SkIntToScalar( 1),
         SkIntToScalar( 1), SkIntToScalar( 1), SkIntToScalar( 1),
     };
-    SkISize kernelSize = SkISize::Make(3, 3);
-    SkScalar gain = SK_Scalar1, bias = 0;
-    SkScalar five = SkIntToScalar(5);
+    const SkISize kernelSize = SkISize::Make(3, 3);
+    const SkScalar gain = SK_Scalar1, bias = 0;
+    const SkScalar five = SkIntToScalar(5);
 
     SkAutoTUnref<SkImage> gradientImage(SkImage::NewFromBitmap(make_gradient_circle(64, 64)));
     SkAutoTUnref<SkImageFilter> gradientSource(SkImageSource::Create(gradientImage));
     SkAutoTUnref<SkImageFilter> blur(SkBlurImageFilter::Create(five, five));
     SkMatrix matrix;
 
     matrix.setTranslate(SK_Scalar1, SK_Scalar1);
     matrix.postRotate(SkIntToScalar(45), SK_Scalar1, SK_Scalar1);
 
     SkRTreeFactory factory;
@@ skipping 44 matching lines @@
         { "erode", SkErodeImageFilter::Create(2, 3) },
         { "tile", SkTileImageFilter::Create(SkRect::MakeXYWH(0, 0, 50, 50),
                                             SkRect::MakeXYWH(0, 0, 100, 100), nullptr) },
         { "matrix", SkImageFilter::CreateMatrixFilter(matrix, kLow_SkFilterQuality) },
         { "blur and offset", SkOffsetImageFilter::Create(five, five, blur.get()) },
         { "picture and blur", SkBlurImageFilter::Create(five, five, pictureFilter.get()) },
         { "rect shader and blur", SkBlurImageFilter::Create(five, five, rectShaderFilter.get()) },
     };
 
     SkBitmap untiledResult, tiledResult;
-    int width = 64, height = 64;
+    const int width = 64, height = 64;
     untiledResult.allocN32Pixels(width, height);
     tiledResult.allocN32Pixels(width, height);
     SkCanvas tiledCanvas(tiledResult);
     SkCanvas untiledCanvas(untiledResult);
     int tileSize = 8;
 
     for (int scale = 1; scale <= 2; ++scale) {
         for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
             tiledCanvas.clear(0);
             untiledCanvas.clear(0);
@@ skipping 806 matching lines @@
                                                          SkSurface::kNo_Budgeted,
                                                          SkImageInfo::MakeN32Premul(1, 1),
                                                          0,
                                                          &props,
                                                          SkGpuDevice::kUninit_InitContents));
     SkImageFilter::Proxy proxy(device);
 
     test_negative_blur_sigma(&proxy, reporter);
 }
 #endif