Pad inval rects to compensate for Skia's hairline stroke

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2716 matching lines @@
       layerDirtyRect.move(-layer->offsetFromLayoutObject());
       layer->setNeedsDisplayInRect(layerDirtyRect, invalidationReason, client);
     }
   }
 
   IntRect r;
   PaintInvalidationReason invalidationReason;
   const DisplayItemClient& client;
 };
 
+IntRect CompositedLayerMapping::adjustedInvalRect(const LayoutRect& r) const {
+  // Skia's hairline stroke may extend .5 units outside the computed path
+  // bounds.  Pad defensively.
+  static constexpr float kInvalRectPadding = .5f;
+
+  LayoutRect adjustedRect(r);
+  adjustedRect.inflate(LayoutUnit(kInvalRectPadding));
+  adjustedRect.intersect(m_compositedBounds);
+  adjustedRect.move(m_owningLayer.subpixelAccumulation());
+
+  return enclosingIntRect(adjustedRect);
+}
+
 void CompositedLayerMapping::setContentsNeedDisplayInRect(
     const LayoutRect& r,
     PaintInvalidationReason invalidationReason,
     const DisplayItemClient& client) {
   DCHECK(!m_owningLayer.layoutObject()->usesCompositedScrolling());
   // TODO(wangxianzhu): Enable the following assert after paint invalidation for
   // spv2 is ready.
   // ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
-  SetContentsNeedsDisplayInRectFunctor functor = {
-      enclosingIntRect(LayoutRect(
-          r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
-      invalidationReason, client};
+  SetContentsNeedsDisplayInRectFunctor functor = {adjustedInvalRect(r),
+                                                  invalidationReason, client};
   ApplyToGraphicsLayers(this, functor, ApplyToContentLayers);
 }
 
 void CompositedLayerMapping::setNonScrollingContentsNeedDisplayInRect(
     const LayoutRect& r,
     PaintInvalidationReason invalidationReason,
     const DisplayItemClient& client) {
   DCHECK(m_owningLayer.layoutObject()->usesCompositedScrolling());
   // TODO(wangxianzhu): Enable the following assert after paint invalidation for
   // spv2 is ready.
   // ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
-  SetContentsNeedsDisplayInRectFunctor functor = {
-      enclosingIntRect(LayoutRect(
-          r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
-      invalidationReason, client};
+  SetContentsNeedsDisplayInRectFunctor functor = {adjustedInvalRect(r),
+                                                  invalidationReason, client};
   ApplyToGraphicsLayers(this, functor, ApplyToNonScrollingContentLayers);
 }
 
 void CompositedLayerMapping::setScrollingContentsNeedDisplayInRect(
     const LayoutRect& r,
     PaintInvalidationReason invalidationReason,
     const DisplayItemClient& client) {
   DCHECK(m_owningLayer.layoutObject()->usesCompositedScrolling());
   // TODO(wangxianzhu): Enable the following assert after paint invalidation for
   // spv2 is ready.
   // ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
-  SetContentsNeedsDisplayInRectFunctor functor = {
-      enclosingIntRect(LayoutRect(
-          r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
-      invalidationReason, client};
+  SetContentsNeedsDisplayInRectFunctor functor = {adjustedInvalRect(r),
+                                                  invalidationReason, client};
   ApplyToGraphicsLayers(this, functor, ApplyToScrollingContentLayers);
 }
 
 const GraphicsLayerPaintInfo* CompositedLayerMapping::containingSquashedLayer(
     const LayoutObject* layoutObject,
     const Vector<GraphicsLayerPaintInfo>& layers,
     unsigned maxSquashedLayerIndex) {
   if (!layoutObject)
     return nullptr;
   for (size_t i = 0; i < layers.size() && i < maxSquashedLayerIndex; ++i) {
@@ skipping 652 matching lines @@
   } else if (graphicsLayer == m_decorationOutlineLayer.get()) {
     name = "Decoration Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink