Adding support for blending in cc::SoftwareRenderer

cc/output/renderer_pixeltest.cc

Index: cc/output/renderer_pixeltest.cc
diff --git a/cc/output/renderer_pixeltest.cc b/cc/output/renderer_pixeltest.cc
index 70c68fea2f2c348ee357c3e17dfc3155bd54df1b..c60526c9a10d58968658ce8d779ab9a7d2fbc24e 100644
--- a/cc/output/renderer_pixeltest.cc
+++ b/cc/output/renderer_pixeltest.cc
@@ -161,13 +161,6 @@ typedef ::testing::Types<GLRenderer,
                          SoftwareRendererWithExpandedViewport> RendererTypes;
 TYPED_TEST_CASE(RendererPixelTest, RendererTypes);
 
-// All pixels can be off by one, but any more than that is an error.
-class FuzzyPixelOffByOneComparator : public FuzzyPixelComparator {
- public:
-  explicit FuzzyPixelOffByOneComparator(bool discard_alpha)
-    : FuzzyPixelComparator(discard_alpha, 100.f, 0.f, 1.f, 1, 0) {}
-};
-
 template <typename RendererType>
 class FuzzyForSoftwareOnlyPixelComparator : public PixelComparator {
  public: