Adding support for blending in cc::SoftwareRenderer

cc/trees/layer_tree_host_pixeltest_blending.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/layers/solid_color_layer.h"
 #include "cc/layers/texture_layer.h"
 #include "cc/test/layer_tree_pixel_test.h"
+#include "cc/test/pixel_comparator.h"
 
 #if !defined(OS_ANDROID)
 
 namespace cc {
 namespace {
 
 SkXfermode::Mode const kBlendModes[] = {
     SkXfermode::kSrcOver_Mode,   SkXfermode::kScreen_Mode,
     SkXfermode::kOverlay_Mode,   SkXfermode::kDarken_Mode,
     SkXfermode::kLighten_Mode,   SkXfermode::kColorDodge_Mode,
     SkXfermode::kColorBurn_Mode, SkXfermode::kHardLight_Mode,
     SkXfermode::kSoftLight_Mode, SkXfermode::kDifference_Mode,
     SkXfermode::kExclusion_Mode, SkXfermode::kMultiply_Mode,
     SkXfermode::kHue_Mode,       SkXfermode::kSaturation_Mode,
     SkXfermode::kColor_Mode,     SkXfermode::kLuminosity_Mode};
 
 const int kBlendModesCount = arraysize(kBlendModes);
 
 class LayerTreeHostBlendingPixelTest : public LayerTreePixelTest {
+ public:
+  LayerTreeHostBlendingPixelTest() {
+    pixel_comparator_.reset(new FuzzyPixelOffByOneComparator(true));
+  }
+
  protected:
   void RunBlendingWithRootPixelTestType(PixelTestType type) {
     const int kLaneWidth = 15;
     const int kLaneHeight = kBlendModesCount * kLaneWidth;
     const int kRootSize = (kBlendModesCount + 2) * kLaneWidth;
 
     scoped_refptr<SolidColorLayer> background =
         CreateSolidColorLayer(gfx::Rect(kRootSize, kRootSize), kCSSOrange);
 
     // Orange child layers will blend with the green background
@@ skipping 38 matching lines @@
     RunPixelTest(type,
                  root,
                  base::FilePath(FILE_PATH_LITERAL("blending_transparent.png")));
   }
 };
 
 TEST_F(LayerTreeHostBlendingPixelTest, BlendingWithRoot_GL) {
   RunBlendingWithRootPixelTestType(GL_WITH_BITMAP);
 }
 
+TEST_F(LayerTreeHostBlendingPixelTest, BlendingWithRoot_Software) {
+  RunBlendingWithRootPixelTestType(SOFTWARE_WITH_BITMAP);
+}
+
 TEST_F(LayerTreeHostBlendingPixelTest, BlendingWithBackgroundFilter) {
   const int kLaneWidth = 15;
   const int kLaneHeight = kBlendModesCount * kLaneWidth;
   const int kRootSize = (kBlendModesCount + 2) * kLaneWidth;
 
   scoped_refptr<SolidColorLayer> background =
       CreateSolidColorLayer(gfx::Rect(kRootSize, kRootSize), kCSSOrange);
 
   // Orange child layers have a background filter set and they will blend with
   // the green background
@@ skipping 12 matching lines @@
 
   RunPixelTest(GL_WITH_BITMAP,
                background,
                base::FilePath(FILE_PATH_LITERAL("blending_and_filter.png")));
 }
 
 TEST_F(LayerTreeHostBlendingPixelTest, BlendingWithTransparent_GL) {
   RunBlendingWithTransparentPixelTestType(GL_WITH_BITMAP);
 }
 
+TEST_F(LayerTreeHostBlendingPixelTest, BlendingWithTransparent_Software) {
+  RunBlendingWithTransparentPixelTestType(SOFTWARE_WITH_BITMAP);
+}
+
 }  // namespace
 }  // namespace cc
 
 #endif  // OS_ANDROID