Switch back to the original brightness filter implementation.

cc/render_surface_filters_unittest.cc

Index: cc/render_surface_filters_unittest.cc
diff --git a/cc/render_surface_filters_unittest.cc b/cc/render_surface_filters_unittest.cc
index ceecd0d9b92cef9d643f5a8e567842acb1ee0176..d5dd9eb3d4ed19c2865aa063f15b22a274f305b7 100644
--- a/cc/render_surface_filters_unittest.cc
+++ b/cc/render_surface_filters_unittest.cc
@@ -55,9 +55,17 @@ TEST(RenderSurfaceFiltersTest, testColorMatrixFiltersCombined)
     EXPECT_TRUE(isCombined(WebFilterOperation::createOpacityFilter(0.5)));
     EXPECT_TRUE(isCombined(WebFilterOperation::createOpacityFilter(1)));
 
-    // Several filters should never combine: brightness(amount > 0), blur, drop-shadow.
-    EXPECT_FALSE(isCombined(WebFilterOperation::createBrightnessFilter(0.5)));
-    EXPECT_FALSE(isCombined(WebFilterOperation::createBrightnessFilter(1)));
+    // Brightness combines when amount <= 1
+    EXPECT_TRUE(isCombined(WebFilterOperation::createBrightnessFilter(0.5)));
+    EXPECT_TRUE(isCombined(WebFilterOperation::createBrightnessFilter(1)));
+    EXPECT_FALSE(isCombined(WebFilterOperation::createBrightnessFilter(1.5)));
+
+    // SaturatingBrightness combines only when amount == 0
+    EXPECT_TRUE(isCombined(WebFilterOperation::createSaturatingBrightnessFilter(0)));
+    EXPECT_FALSE(isCombined(WebFilterOperation::createSaturatingBrightnessFilter(0.5)));
+    EXPECT_FALSE(isCombined(WebFilterOperation::createSaturatingBrightnessFilter(1)));
+
+    // Several filters should never combine: blur, drop-shadow.
     EXPECT_FALSE(isCombined(WebFilterOperation::createBlurFilter(3)));
     EXPECT_FALSE(isCombined(WebFilterOperation::createDropShadowFilter(WebPoint(2, 2), 3, 0xffffffff)));
 
@@ -102,8 +110,8 @@ TEST(RenderSurfaceFiltersTest, testColorMatrixFiltersCombined)
 
 TEST(RenderSurfaceFiltersTest, testOptimize)
 {
-    WebFilterOperation combines(WebFilterOperation::createBrightnessFilter(0));
-    WebFilterOperation doesntCombine(WebFilterOperation::createBrightnessFilter(1));
+    WebFilterOperation combines(WebFilterOperation::createBrightnessFilter(1));
+    WebFilterOperation doesntCombine(WebFilterOperation::createBrightnessFilter(1.5));
 
     WebFilterOperations filters;
     WebFilterOperations optimized = RenderSurfaceFilters::optimize(filters);