Add unit test for crbug.com/570232

tests/BlurTest.cpp

Index: tests/BlurTest.cpp
diff --git a/tests/BlurTest.cpp b/tests/BlurTest.cpp
index 556930e6e936c1af0145e011e4274d09e7779f8e..9806611cfbeb9d52f9ededc1651844f70868a739 100644
--- a/tests/BlurTest.cpp
+++ b/tests/BlurTest.cpp
@@ -558,4 +558,25 @@ DEF_TEST(BlurAsABlur, reporter) {
     }
 }
 
+#if SK_SUPPORT_GPU
+
+// This exercises the problem discovered in crbug.com/570232. The return value from 
+// SkBlurMask::BoxBlur wasn't being checked in SkBlurMaskFilter.cpp::GrRRectBlurEffect::Create
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SmallBoxBlurBug, reporter, ctx) {
+
+    SkImageInfo info = SkImageInfo::MakeN32Premul(128, 128);
+    SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTarget(ctx, SkSurface::kNo_Budgeted, info));
+    SkCanvas* canvas = surface->getCanvas();
+
+    SkRect r = SkRect::MakeXYWH(10, 10, 100, 100);
+    SkRRect rr = SkRRect::MakeRectXY(r, 10, 10);
+
+    SkPaint p;
+    p.setMaskFilter(SkBlurMaskFilter::Create(kNormal_SkBlurStyle, 0.01f))->unref();
+
+    canvas->drawRRect(rr, p);
+}
+
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////////////////