cc: Add a pixel test for background blur outsets.

cc/trees/layer_tree_host_pixeltest_filters.cc

Index: cc/trees/layer_tree_host_pixeltest_filters.cc
diff --git a/cc/trees/layer_tree_host_pixeltest_filters.cc b/cc/trees/layer_tree_host_pixeltest_filters.cc
index 37d2931dfa0e9cbf5173d45e597f261e6bb12d38..b633d76c0a2386e47c484dc1fc975e2c69d42f84 100644
--- a/cc/trees/layer_tree_host_pixeltest_filters.cc
+++ b/cc/trees/layer_tree_host_pixeltest_filters.cc
@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "build/build_config.h"
 #include "cc/test/layer_tree_pixel_test.h"
+#include "cc/test/pixel_comparator.h"
 
 #if !defined(OS_ANDROID)
 
@@ -33,6 +35,84 @@ TEST_F(LayerTreeHostFiltersPixelTest, BackgroundFilterBlur) {
                    "background_filter_blur.png")));
 }
 
+TEST_F(LayerTreeHostFiltersPixelTest, BackgroundFilterBlurOutsets) {
+  scoped_refptr<SolidColorLayer> background = CreateSolidColorLayer(
+      gfx::Rect(200, 200), SK_ColorWHITE);
+
+  // The green border is outside the layer with background blur, but the
+  // background blur should use pixels from outside its layer borders, up to the
+  // radius of the blur effect. So the border should be blurred underneath the
+  // top layer causing the green to bleed under the transparent layer, but not
+  // in the 1px region between the transparent layer and the green border.
+  scoped_refptr<SolidColorLayer> green_border = CreateSolidColorLayerWithBorder(
+      gfx::Rect(1, 1, 198, 198), SK_ColorWHITE, 10, kCSSGreen);
+  scoped_refptr<SolidColorLayer> blur = CreateSolidColorLayer(
+      gfx::Rect(12, 12, 176, 176), SK_ColorTRANSPARENT);
+  background->AddChild(green_border);
+  background->AddChild(blur);
+
+  WebKit::WebFilterOperations filters;
+  filters.append(WebKit::WebFilterOperation::createBlurFilter(5));
+  blur->SetBackgroundFilters(filters);
+
+  RunPixelTest(background,
+               base::FilePath(FILE_PATH_LITERAL(
+                   "background_filter_blur_outsets.png")));
+}
+
+TEST_F(LayerTreeHostFiltersPixelTest, BackgroundFilterBlurOffAxis) {
+  scoped_refptr<SolidColorLayer> background = CreateSolidColorLayer(
+      gfx::Rect(200, 200), SK_ColorWHITE);
+
+  // This verifies that the perspective of the clear layer (with black border)
+  // does not influence the blending of the green box behind it. Also verifies
+  // that the blur is correctly clipped inside the transformed clear layer.
+  scoped_refptr<SolidColorLayer> green = CreateSolidColorLayer(
+      gfx::Rect(50, 50, 100, 100), kCSSGreen);
+  scoped_refptr<SolidColorLayer> blur = CreateSolidColorLayerWithBorder(
+      gfx::Rect(30, 30, 120, 120), SK_ColorTRANSPARENT, 1, SK_ColorBLACK);
+  background->AddChild(green);
+  background->AddChild(blur);
+
+  background->SetPreserves3d(true);
+  gfx::Transform background_transform;
+  background_transform.ApplyPerspectiveDepth(200.0);
+  background->SetTransform(background_transform);
+
+  blur->SetPreserves3d(true);
+  gfx::Transform blur_transform;
+  blur_transform.Translate(55.0, 65.0);
+  blur_transform.RotateAboutXAxis(85.0);
+  blur_transform.RotateAboutYAxis(180.0);
+  blur_transform.RotateAboutZAxis(20.0);
+  blur_transform.Translate(-60.0, -60.0);
+  blur->SetTransform(blur_transform);
+
+  WebKit::WebFilterOperations filters;
+  filters.append(WebKit::WebFilterOperation::createBlurFilter(2));
+  blur->SetBackgroundFilters(filters);
+
+#if defined(OS_WIN)
+  // Windows has 4 pixels off by 1: crbug.com/225027
+  float percentage_pixels_large_error = 0.01f;  // 4px / (200*200)
+  float percentage_pixels_small_error = 0.01f;  // 4px / (200*200)
+  float average_error_allowed_in_bad_pixels = 1.f;
+  int large_error_allowed = 1;
+  int small_error_allowed = 1;
+  pixel_comparator_.reset(new FuzzyPixelComparator(
+      true,  // discard_alpha
+      percentage_pixels_large_error,
+      percentage_pixels_small_error,
+      average_error_allowed_in_bad_pixels,
+      large_error_allowed,
+      small_error_allowed));
+#endif
+
+  RunPixelTest(background,
+               base::FilePath(FILE_PATH_LITERAL(
+                   "background_filter_blur_off_axis.png")));
+}
+
 }  // namespace
 }  // namespace cc