Stop clipping to visual rect bounds in PLC::CalculateBackgroundClipRect

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

Index: third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
index da24d7aaabd5bd373b245de256182977fb82bc7a..902295373b5c159d49ff7b391906e4bbabcceffa 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
@@ -205,7 +205,8 @@ LayoutRect PaintLayerClipper::LocalClipRect(
   ClipRectsContext context(&clipping_root_layer, kPaintingClipRects);
   if (use_geometry_mapper_) {
     ClipRect clip_rect;
-    CalculateBackgroundClipRectWithGeometryMapper(context, clip_rect);
+    CalculateBackgroundClipRectWithGeometryMapper(context, clip_rect,
+                                                  ShouldClipOverflow(context));
     LayoutRect premapped_rect = clip_rect.Rect();
 
     // The rect now needs to be transformed to the local space of this
@@ -279,7 +280,8 @@ void PaintLayerClipper::CalculateRectsWithGeometryMapper(
     background_rect = ClipRect(LayoutRect(LayoutRect::InfiniteIntRect()));
     foreground_rect = ClipRect(LayoutRect(LayoutRect::InfiniteIntRect()));
   } else {
-    CalculateBackgroundClipRectWithGeometryMapper(context, background_rect);
+    CalculateBackgroundClipRectWithGeometryMapper(context, background_rect,
+                                                  ShouldClipOverflow(context));
     background_rect.Move(context.sub_pixel_accumulation);
     background_rect.Intersect(paint_dirty_rect);
 
@@ -426,7 +428,8 @@ static ClipRect BackgroundClipRectForPosition(const ClipRects& parent_rects,
 
 void PaintLayerClipper::CalculateBackgroundClipRectWithGeometryMapper(
     const ClipRectsContext& context,
-    ClipRect& output) const {
+    ClipRect& output,
+    bool should_clip_to_visual_overflow) const {
   DCHECK(use_geometry_mapper_);
   PropertyTreeState source_property_tree_state(nullptr, nullptr, nullptr);
   PropertyTreeState destination_property_tree_state(nullptr, nullptr, nullptr);
@@ -457,7 +460,7 @@ void PaintLayerClipper::CalculateBackgroundClipRectWithGeometryMapper(
   // of transforms. Tight results are required for most use cases of these
   // rects, so we should add methods to GeometryMapper that guarantee there
   // are tight results, or else signal an error.
-  if (ShouldClipOverflow(context)) {
+  if (should_clip_to_visual_overflow) {
     FloatClipRect clip_rect((FloatRect(LocalVisualRect())));
     clip_rect.MoveBy(FloatPoint(layer_.GetLayoutObject().PaintOffset()));
     GeometryMapper::SourceToDestinationVisualRect(
@@ -468,6 +471,8 @@ void PaintLayerClipper::CalculateBackgroundClipRectWithGeometryMapper(
         GeometryMapper::SourceToDestinationClipRect(
             source_property_tree_state, destination_property_tree_state);
     output.SetRect(clipped_rect_in_root_layer_space);
+    if (clipped_rect_in_root_layer_space.IsInfinite())
+      return;
   }
 
   output.MoveBy(-context.root_layer->GetLayoutObject().PaintOffset());
@@ -529,7 +534,7 @@ void PaintLayerClipper::CalculateBackgroundClipRect(
       return;
     }
 
-    CalculateBackgroundClipRectWithGeometryMapper(context, output);
+    CalculateBackgroundClipRectWithGeometryMapper(context, output, false);
 #ifdef CHECK_CLIP_RECTS
     ClipRect testBackgroundClipRect =
         PaintLayerClipper(m_layer, nullptr).backgroundClipRect(context);