cc: Add layer-based pixel tests.

cc/layer_tree_host_pixeltest_filters.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/test/layer_tree_pixel_test.h"
+
+#if !defined(OS_ANDROID)
+
+namespace cc {
+namespace {
+
+class LayerTreeHostFiltersPixelTest : public LayerTreePixelTest {};
+
+TEST_F(LayerTreeHostFiltersPixelTest, BackgroundFilterBlur) {
+  scoped_refptr<SolidColorLayer> background = CreateSolidColorLayer(
+      gfx::Rect(200, 200), SK_ColorWHITE);
+
+  // The green box is entirely behind a layer with background blur, so it
+  // should appear blurred on its edges.
+  scoped_refptr<SolidColorLayer> green = CreateSolidColorLayer(
+      gfx::Rect(50, 50, 100, 100), kCSSGreen);
+  scoped_refptr<SolidColorLayer> blur = CreateSolidColorLayer(
+      gfx::Rect(30, 30, 140, 140), SK_ColorTRANSPARENT);
+  background->AddChild(green);
+  background->AddChild(blur);
+
+  WebKit::WebFilterOperations filters;
+  filters.append(WebKit::WebFilterOperation::createBlurFilter(2));
+  blur->SetBackgroundFilters(filters);
+
+  RunPixelTest(background,
+               base::FilePath(FILE_PATH_LITERAL(
+                   "background_filter_blur.png")));
+}
+
+}  // namespace
+}  // namespace cc
+
+#endif  // OS_ANDROID