Add flag for tracking descendant paint property updates

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 22c9acdecad7fc9b01f776650e8885a8d5bcc3b9..8ccfd94ac1df8591b0525b2082a01eacd27c33cd 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1472,7 +1472,6 @@ StyleDifference LayoutObject::adjustStyleDifference(
 
       // When transform, opacity, etc. change, paint properties will also change
       // so we need to mark this object as needing an update.
-      // TODO(pdr): Also update in the non-spv2 codepath?
       getMutableForPainting().setNeedsPaintPropertyUpdate();
     }
   } else {
@@ -2508,7 +2507,7 @@ LayoutObject* LayoutObject::container(const LayoutBoxModelObject* ancestor,
   return o;
 }
 
-LayoutObject* LayoutObject::paintInvalidationParent() const {
+inline LayoutObject* LayoutObject::paintInvalidationParent() const {
   if (isLayoutView())
     return LayoutAPIShim::layoutObjectFrom(frame()->ownerLayoutItem());
   if (isColumnSpanAll())
@@ -2516,6 +2515,10 @@ LayoutObject* LayoutObject::paintInvalidationParent() const {
   return parent();
 }
 
+LayoutObject* LayoutObject::slowPaintInvalidationParentForTesting() const {
+  return paintInvalidationParent();
+}
+
 bool LayoutObject::isSelectionBorder() const {
   SelectionState st = getSelectionState();
   return st == SelectionStart || st == SelectionEnd || st == SelectionBoth;
@@ -2724,6 +2727,27 @@ void LayoutObject::willBeRemovedFromTree() {
   }
 }
 
+void LayoutObject::setNeedsPaintPropertyUpdate() {
+  m_bitfields.setNeedsPaintPropertyUpdate(true);
+
+  // Mark all ancestors as having a descendant needing paint property updates.
+  // |paintInvalidationParent()| is used to ensure we continue marking across
+  // frame boundaries.
+  LayoutObject* ancestor = paintInvalidationParent();
+  while (ancestor && !ancestor->descendantNeedsPaintPropertyUpdate()) {
+    ancestor->m_bitfields.setDescendantNeedsPaintPropertyUpdate(true);
+    ancestor = ancestor->paintInvalidationParent();
+  }
+}
+
+void LayoutObject::setAncestorsNeedPaintPropertyUpdateForMainThreadScrolling() {
+  LayoutObject* ancestor = paintInvalidationParent();
+  while (ancestor) {
+    ancestor->setNeedsPaintPropertyUpdate();
+    ancestor = ancestor->paintInvalidationParent();
+  }
+}
+
 void LayoutObject::maybeClearIsScrollAnchorObject() {
   if (!m_bitfields.isScrollAnchorObject())
     return;