Add test for previously unflattenables

tests/FlattenableFactoryToName.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkAlphaThresholdFilter.h"
+#include "SkImage.h"
+#include "Test.h"
+
+static void test_flattenable(skiatest::Reporter* r,
+                             const SkFlattenable* f,
+                             const char* desc) {
+    if (f) {
+        SkFlattenable::Factory factory = f->getFactory();
+        REPORTER_ASSERT(r, factory);
+        if (factory) {
+            if (!SkFlattenable::FactoryToName(factory)) {
+                ERRORF(r, "SkFlattenable::FactoryToName() fails with %s.", desc);
+            }
+        }
+    }
+}
+
+DEF_TEST(FlattenableFactoryToName, r) {
+    SkIRect rects[2];
+    rects[0] = SkIRect::MakeXYWH(0, 150, 500, 200);
+    rects[1] = SkIRect::MakeXYWH(150, 0, 200, 500);
+    SkRegion region;
+    region.setRects(rects, 2);
+    SkAutoTUnref<SkImageFilter> filter( SkAlphaThresholdFilter::Create(region, 0.2f, 0.7f));
+    test_flattenable(r, filter, "SkAlphaThresholdFilter()");
+
+    SkBitmap bm;
+    bm.allocN32Pixels(8, 8);
+    bm.eraseColor(SK_ColorCYAN);
+    SkAutoTUnref<SkImage> image(SkImage::NewFromBitmap(bm));
+    SkAutoTUnref<SkShader> shader(image->newShader(SkShader::kClamp_TileMode,
+                                                   SkShader::kClamp_TileMode));
+    test_flattenable(r, shader, "SkImage::newShader()");
+}