factories should return baseclass, allowing the impl to specialize

tests/ImageFilterTest.cpp

Index: tests/ImageFilterTest.cpp
diff --git a/tests/ImageFilterTest.cpp b/tests/ImageFilterTest.cpp
index b1a017cc52c7b20c9400080c725a08aad81b9d24..cf1bffc802d134b5ee34ab6785f3b3e83edfe233 100644
--- a/tests/ImageFilterTest.cpp
+++ b/tests/ImageFilterTest.cpp
@@ -357,13 +357,8 @@ static void test_negative_blur_sigma(SkImageFilter::Proxy* proxy, skiatest::Repo
     int width = 32, height = 32;

[robertphillips, 2015/10/06 11:43:12]

I feel this variable should, at the very least, be const.

[reed1, 2015/10/06 16:59:24]

Done.

     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;