Stop clipping to visual rect bounds in PLC::CalculateBackgroundClipRect

third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp b/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
index 62cd610bfde2b7775e4d80846817e5d5a0884b54..1ca0792fc653084faf2994791a8a483945197c8c 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
@@ -512,4 +512,33 @@ TEST_P(PaintLayerClipperTest, Filter) {
   EXPECT_EQ(LayoutRect(0, 0, 100, 200), foreground_rect.Rect());
 }
 
+TEST_P(PaintLayerClipperTest, CalculateBackgroundClipRectRoot) {
+  SetBodyInnerHTML(
+      "<style>"
+      "  * { margin: 0 }"
+      "  #target { "
+      " position: relative; "
+      "    overflow: hidden;"
+      "    width: 100px; height: 200px;"
+      "  }"
+      "</style>"
+      "<div id='target'></div>");
+
+  PaintLayer* target =
+      ToLayoutBoxModelObject(GetLayoutObjectByElementId("target"))->Layer();
+  ClipRectsContext context(target, kUncachedClipRects);
+  PaintLayer::GeometryMapperOption option = PaintLayer::kDoNotUseGeometryMapper;
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
+    option = PaintLayer::kUseGeometryMapper;
+  ClipRect output;
+
+  target->Clipper(option).CalculateBackgroundClipRect(context, output);
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
+    EXPECT_EQ(LayoutRect(FloatRect(LayoutRect::InfiniteIntRect())),
+              output.Rect());
+  } else {
+    EXPECT_EQ(LayoutRect(LayoutRect::InfiniteIntRect()), output.Rect());
+  }
+}
+
 }  // namespace blink