Fix border radius on composited children.

third_party/WebKit/Source/core/paint/PaintLayer.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 1547 matching lines @@
                               layoutObject()->style()->resize() != RESIZE_NONE);
 }
 
 void PaintLayer::appendSingleFragmentIgnoringPagination(
     PaintLayerFragments& fragments,
     const PaintLayer* rootLayer,
     const LayoutRect& dirtyRect,
     ClipRectsCacheSlot clipRectsCacheSlot,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
+    bool paintingAncestorClippingMask,
     const LayoutPoint* offsetFromRoot,
     const LayoutSize& subPixelAccumulation) {
   PaintLayerFragment fragment;
   ClipRectsContext clipRectsContext(rootLayer, clipRectsCacheSlot,
                                     overlayScrollbarClipBehavior,
                                     subPixelAccumulation);
   if (respectOverflowClip == IgnoreOverflowClip)
     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);
 }
 
 bool PaintLayer::shouldFragmentCompositedBounds(
     const PaintLayer* compositingLayer) const {
   // Composited layers may not be fragmented.
   return enclosingPaginationLayer() &&
          !compositingLayer->enclosingPaginationLayer();
 }
 
 void PaintLayer::collectFragments(
     PaintLayerFragments& fragments,
     const PaintLayer* rootLayer,
     const LayoutRect& dirtyRect,
     ClipRectsCacheSlot clipRectsCacheSlot,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
+    bool paintingAncestorClippingMask,
     const LayoutPoint* offsetFromRoot,
     const LayoutSize& subPixelAccumulation,
     const LayoutRect* layerBoundingBox) {
   if (!enclosingPaginationLayer()) {
     // 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;
   }
 
   // Compute our offset within the enclosing pagination layer.
   LayoutPoint offsetWithinPaginatedLayer;
   convertToLayerCoords(enclosingPaginationLayer(), offsetWithinPaginatedLayer);
 
   // Calculate clip rects relative to the enclosingPaginationLayer. The purpose
   // of this call is to determine our bounds clipped to intermediate layers
   // between us and the pagination context. It's important to minimize the
   // number of fragments we need to create and this helps with that.
   ClipRectsContext paginationClipRectsContext(enclosingPaginationLayer(),
                                               clipRectsCacheSlot,
                                               overlayScrollbarClipBehavior);
   if (respectOverflowClip == IgnoreOverflowClip)
     paginationClipRectsContext.setIgnoreOverflowClip();
   LayoutRect layerBoundsInFlowThread;
   ClipRect backgroundRectInFlowThread;
   ClipRect foregroundRectInFlowThread;
   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 =
       layerBoundingBox ? *layerBoundingBox
                        : physicalBoundingBox(offsetWithinPaginatedLayer);
   layerBoundingBoxInFlowThread.intersect(backgroundRectInFlowThread.rect());
 
   LayoutFlowThread* enclosingFlowThread =
       toLayoutFlowThread(enclosingPaginationLayer()->layoutObject());
   // Visual offset from the root layer to the nearest fragmentation context.
@@ skipping 510 matching lines @@
     double* zOffset,
     ClipRectsCacheSlot clipRectsCacheSlot) {
   PaintLayerFragments enclosingPaginationFragments;
   LayoutPoint offsetOfPaginationLayerFromRoot;
   // FIXME: We're missing a sub-pixel offset here crbug.com/348728
   LayoutRect transformedExtent = transparencyClipBox(
       this, enclosingPaginationLayer(), HitTestingTransparencyClipBox,
       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) {
     const PaintLayerFragment& fragment = enclosingPaginationFragments.at(i);
 
     // Apply the page/column clip for this fragment, as well as any clips
     // established by layers in between us and the enclosing pagination layer.
     LayoutRect clipRect = fragment.backgroundRect.rect();
 
     // Now compute the clips within a given fragment
@@ skipping 1052 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
     return;
   }
   showLayerTree(layoutObject->enclosingLayer());
 }
 #endif