cc: Enable composited border-radius scrolling.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 482 matching lines @@
   if (context.ShouldRespectRootLayerClip()) {
     const auto* ancestor_css_clip = ancestor_properties->CssClip();
     if (ancestor_css_clip) {
       DCHECK_EQ(destination_property_tree_state.Clip(),
                 ancestor_css_clip);
       destination_property_tree_state.SetClip(ancestor_css_clip->Parent());
     }
   } else {
     const auto* ancestor_overflow_clip = ancestor_properties->OverflowClip();
     if (ancestor_overflow_clip) {
-      DCHECK_EQ(destination_property_tree_state.Clip(),
-                ancestor_overflow_clip->Parent());
+      if (const auto* ancestor_rounded_clip =

[chrishtr, 2017/06/21 15:26:56]

Put #ifdef DCHECK_IS_ON around these conditionals.

+              ancestor_properties->InnerBorderRadiusClip()) {
+        DCHECK_EQ(destination_property_tree_state.Clip(),
+                  ancestor_rounded_clip->Parent());
+        DCHECK_EQ(ancestor_rounded_clip, ancestor_overflow_clip->Parent());
+      } else {
+        DCHECK_EQ(destination_property_tree_state.Clip(),
+                  ancestor_overflow_clip->Parent());
+      }
       destination_property_tree_state.SetClip(ancestor_overflow_clip);
     }
   }
 }
 
 LayoutRect PaintLayerClipper::LocalVisualRect() const {
   const LayoutObject& layout_object = layer_.GetLayoutObject();
   // The LayoutView is special since its overflow clipping rect may be larger
   // than its box rect (crbug.com/492871).
   LayoutRect layer_bounds_with_visual_overflow =
@@ skipping 73 matching lines @@
   DCHECK(!use_geometry_mapper_);
   ClipRectsContext context(root_layer, kPaintingClipRects,
                            kIgnorePlatformOverlayScrollbarSize,
                            subpixel_accumulation);
   if (respect_overflow_clip == kIgnoreOverflowClip)
     context.SetIgnoreOverflowClip();
   return GetClipRects(context);
 }
 
 }  // namespace blink