Remove multicol special-cases from invalidation and the pre-paint tree walk

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

Index: third_party/WebKit/Source/core/paint/PaintInvalidator.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp b/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp
index ae4cf35ce087eaf0a582b491f03f231c4c0db644..d8a29110e9f5305f4cfa0ad5768c2184cc007f4d 100644
--- a/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintInvalidator.cpp
@@ -199,8 +199,10 @@ void PaintInvalidator::updatePaintingLayer(const LayoutObject& object,
   if (object.hasLayer() &&
       toLayoutBoxModelObject(object).hasSelfPaintingLayer()) {
     context.paintingLayer = toLayoutBoxModelObject(object).layer();
-  } else if (object.isFloating() && !object.parent()->isLayoutBlock()) {
-    // See LayoutObject::paintingLayer() for specialty of floating objects.
+  } else if (object.isColumnSpanAll() ||
+             (object.isFloating() && !object.parent()->isLayoutBlock())) {
+    // See LayoutObject::paintingLayer() for the special-cases of out-of-flow

[Xianzhu, 2017/01/07 01:12:08]

s/out-of-flow floating/floating under inline/.

+    // floating and multicolumn.
     context.paintingLayer = object.paintingLayer();
   }