Add support for converting cc::FilterOperations into an SkImageFilter

cc/output/filter_operations_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/filter_operations.h"
+#include "skia/ext/refptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/effects/SkBlurImageFilter.h"
 #include "ui/gfx/point.h"
 
 namespace cc {
 namespace {
 
 TEST(FilterOperationsTest, GetOutsetsBlur) {
   FilterOperations ops;
   ops.Append(FilterOperation::CreateBlurFilter(20));
   int top, right, bottom, left;
   top = right = bottom = left = 0;
@@ skipping 473 matching lines @@
   FilterOperation blended = FilterOperation::Blend(&filter, NULL, 0.25);
   FilterOperation expected =
       FilterOperation::CreateSaturatingBrightnessFilter(0.75f);
   EXPECT_EQ(expected, blended);
 
   blended = FilterOperation::Blend(NULL, &filter, 0.25);
   expected = FilterOperation::CreateSaturatingBrightnessFilter(0.25f);
   EXPECT_EQ(expected, blended);
 }
 
+TEST(FilterOperationsTest, BlendReferenceFilters) {
+  skia::RefPtr<SkImageFilter> from_filter = skia::AdoptRef(
+      new SkBlurImageFilter(1.f, 1.f));
+  skia::RefPtr<SkImageFilter> to_filter = skia::AdoptRef(
+      new SkBlurImageFilter(2.f, 2.f));
+  FilterOperation from = FilterOperation::CreateReferenceFilter(from_filter);
+  FilterOperation to = FilterOperation::CreateReferenceFilter(to_filter);
+
+  FilterOperation blended = FilterOperation::Blend(&from, &to, -0.75);
+  EXPECT_EQ(from, blended);
+
+  blended = FilterOperation::Blend(&from, &to, 0.5);
+  EXPECT_EQ(from, blended);
+
+  blended = FilterOperation::Blend(&from, &to, 0.6);
+  EXPECT_EQ(to, blended);
+
+  blended = FilterOperation::Blend(&from, &to, 1.5);
+  EXPECT_EQ(to, blended);
+}
+
+TEST(FilterOperationsTest, BlendReferenceWithNull) {
+  skia::RefPtr<SkImageFilter> image_filter = skia::AdoptRef(
+      new SkBlurImageFilter(1.f, 1.f));
+  FilterOperation filter = FilterOperation::CreateReferenceFilter(image_filter);

[danakj, 2013/09/09 22:04:50]

nit: s/filter/from/

[ajuma, 2013/09/10 21:17:58]

This is used as the 'from' filter in the first two calls to Blend below, but as
the 'to' filter in the two calls that follow.

+
+  FilterOperation blended = FilterOperation::Blend(&filter, NULL, 0.25);
+  EXPECT_EQ(filter, blended);
+  blended = FilterOperation::Blend(&filter, NULL, 0.75);
+  EXPECT_EQ(FilterOperation::CreateEmptyFilter(), blended);
+
+  blended = FilterOperation::Blend(NULL, &filter, 0.25);
+  EXPECT_EQ(FilterOperation::CreateEmptyFilter(), blended);
+  blended = FilterOperation::Blend(NULL, &filter, 0.75);
+  EXPECT_EQ(filter, blended);
+}
+
 // Tests blending non-empty sequences that have the same length and matching
 // operations.
 TEST(FilterOperationsTest, BlendMatchingSequences) {
   FilterOperations from;
   FilterOperations to;
 
   from.Append(FilterOperation::CreateBlurFilter(0.f));
   to.Append(FilterOperation::CreateBlurFilter(2.f));
 
   from.Append(FilterOperation::CreateSaturateFilter(4.f));
@@ skipping 109 matching lines @@
   blended = to.Blend(from, -0.75);
   EXPECT_EQ(to, blended);
   blended = to.Blend(from, 0.75);
   EXPECT_EQ(to, blended);
   blended = to.Blend(from, 1.5);
   EXPECT_EQ(to, blended);
 }
 
 }  // namespace
 }  // namespace cc