Revert of Remove PaintInfo's paintingRoot

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

Index: third_party/WebKit/Source/core/paint/PaintInfo.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintInfo.cpp b/third_party/WebKit/Source/core/paint/PaintInfo.cpp
index 7ada3bcde613dbf473b6b32227dc987b5796959d..91de13e37a6ed8730dd3b5c96f6b988216a65ad4 100644
--- a/third_party/WebKit/Source/core/paint/PaintInfo.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintInfo.cpp
@@ -6,6 +6,23 @@
 
 namespace blink {
 
+void PaintInfo::updatePaintingRootForChildren(const LayoutObject* layoutObject)
+{
+    if (!paintingRoot)
+        return;
+
+    // If we're the painting root, kids draw normally, and see root of nullptr.
+    if (paintingRoot == layoutObject) {
+        paintingRoot = nullptr;
+        return;
+    }
+}
+
+bool PaintInfo::shouldPaintWithinRoot(const LayoutObject* layoutObject) const
+{
+    return !paintingRoot || paintingRoot == layoutObject;
+}
+
 void PaintInfo::updateCullRect(const AffineTransform& localToParentTransform)
 {
     m_cullRect.updateCullRect(localToParentTransform);