Fix border radius on composited children.

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 71347c9ed0c82e8c6d1e1a8cb69c0e963733c402..945f6145d9001df3e957db0c4fd0f54fc21555cf 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
@@ -319,6 +319,23 @@ void PaintLayerClipper::calculateRects(
     calculateRectsWithGeometryMapper(context, paintDirtyRect, layerBounds,
                                      backgroundRect, foregroundRect,
                                      offsetFromRoot);
+
+    // CSS clip (different than clipping due to overflow) can clip to any box,

[chrishtr, 2016/11/16 23:56:32]

The code you are inserting here is SPv2-specific. Why are you solving that in
this patch?

[Stephen Chennney, 2016/11/17 18:05:48]

I shouldn't be; I think I was being over-zealous. I need to remove it.

+    // even if it falls outside of the border box.
+    LayoutBoxModelObject& layoutObject = *m_layer.layoutObject();
+    LayoutPoint offset;
+    if (offsetFromRoot)
+      offset = *offsetFromRoot;
+    else
+      m_layer.convertToLayerCoords(context.rootLayer, offset);
+    if (layoutObject.hasClip()) {
+      // Clip applies to *us* as well, so go ahead and update the damageRect.
+      LayoutRect newPosClip = toLayoutBox(layoutObject).clipRect(offset);
+      backgroundRect.intersect(newPosClip);
+      backgroundRect.setIsClippedByClipCss();
+      foregroundRect.intersect(newPosClip);
+      foregroundRect.setIsClippedByClipCss();
+    }
     return;
   }
 
@@ -344,9 +361,10 @@ void PaintLayerClipper::calculateRects(
 
   // Update the clip rects that will be passed to child layers.
   if (shouldClipOverflow(context)) {
-    foregroundRect.intersect(
+    LayoutRect offsetOverflowClipRect =
         toLayoutBox(layoutObject)
-            .overflowClipRect(offset, context.overlayScrollbarClipBehavior));
+            .overflowClipRect(offset, context.overlayScrollbarClipBehavior);
+    foregroundRect.intersect(offsetOverflowClipRect);
     if (layoutObject.styleRef().hasBorderRadius())
       foregroundRect.setHasRadius(true);