Fix border radius on composited children.

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

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index f782b1f5fccd6c254b4cc187356ca2afcaa1efb1..e84caa5cab607278c09748cee4a8cced2921af22 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -1565,6 +1565,7 @@ void PaintLayer::appendSingleFragmentIgnoringPagination(
     ClipRectsCacheSlot clipRectsCacheSlot,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
+    bool paintingAncestorClippingMask,
     const LayoutPoint* offsetFromRoot,
     const LayoutSize& subPixelAccumulation) {
   PaintLayerFragment fragment;
@@ -1575,7 +1576,7 @@ void PaintLayer::appendSingleFragmentIgnoringPagination(
     clipRectsContext.setIgnoreOverflowClip();
   clipper().calculateRects(clipRectsContext, dirtyRect, fragment.layerBounds,
                            fragment.backgroundRect, fragment.foregroundRect,
-                           offsetFromRoot);
+                           offsetFromRoot, paintingAncestorClippingMask);

[Stephen Chennney, 2016/11/08 21:42:51]

Here we can create a clipper (PaintLayerClipper) with the clipping container's
layer, but I'm still working on getting offsets and sizes right. Doing so would
avoid the extra argument.

   fragments.append(fragment);
 }
 
@@ -1593,6 +1594,7 @@ void PaintLayer::collectFragments(
     ClipRectsCacheSlot clipRectsCacheSlot,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
+    bool paintingAncestorClippingMask,
     const LayoutPoint* offsetFromRoot,
     const LayoutSize& subPixelAccumulation,
     const LayoutRect* layerBoundingBox) {
@@ -1600,16 +1602,16 @@ void PaintLayer::collectFragments(
     // For unpaginated layers, there is only one fragment.
     appendSingleFragmentIgnoringPagination(
         fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
-        overlayScrollbarClipBehavior, respectOverflowClip, offsetFromRoot,
-        subPixelAccumulation);
+        overlayScrollbarClipBehavior, respectOverflowClip,
+        paintingAncestorClippingMask, offsetFromRoot, subPixelAccumulation);
     return;
   }
 
   if (!shouldFragmentCompositedBounds(rootLayer)) {
     appendSingleFragmentIgnoringPagination(
         fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
-        overlayScrollbarClipBehavior, respectOverflowClip, offsetFromRoot,
-        subPixelAccumulation);
+        overlayScrollbarClipBehavior, respectOverflowClip,
+        paintingAncestorClippingMask, offsetFromRoot, subPixelAccumulation);
     return;
   }
 
@@ -1632,7 +1634,8 @@ void PaintLayer::collectFragments(
   clipper().calculateRects(
       paginationClipRectsContext, LayoutRect(LayoutRect::infiniteIntRect()),
       layerBoundsInFlowThread, backgroundRectInFlowThread,
-      foregroundRectInFlowThread, &offsetWithinPaginatedLayer);
+      foregroundRectInFlowThread, &offsetWithinPaginatedLayer,
+      paintingAncestorClippingMask);
 
   // Take our bounding box within the flow thread and clip it.
   LayoutRect layerBoundingBoxInFlowThread =
@@ -2163,7 +2166,7 @@ PaintLayer* PaintLayer::hitTestTransformedLayerInFragments(
       PaintLayer::RootOfTransparencyClipBox, LayoutSize());
   enclosingPaginationLayer()->collectFragments(
       enclosingPaginationFragments, rootLayer, hitTestRect, clipRectsCacheSlot,
-      ExcludeOverlayScrollbarSizeForHitTesting, RespectOverflowClip,
+      ExcludeOverlayScrollbarSizeForHitTesting, RespectOverflowClip, false,
       &offsetOfPaginationLayerFromRoot, LayoutSize(), &transformedExtent);
 
   for (int i = enclosingPaginationFragments.size() - 1; i >= 0; --i) {