Paint multicol from LayoutNG

third_party/WebKit/Source/core/layout/ng/ng_block_node.cc

Index: third_party/WebKit/Source/core/layout/ng/ng_block_node.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_node.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_node.cc
index a22cbda1f39230492c9c7a24ee14995ec2a683d0..8a8ebddd710ef895376464696352e78a333babda 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_node.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_node.cc
@@ -5,6 +5,8 @@
 #include "core/layout/ng/ng_block_node.h"
 
 #include "core/layout/LayoutBlockFlow.h"
+#include "core/layout/LayoutMultiColumnFlowThread.h"
+#include "core/layout/LayoutMultiColumnSet.h"
 #include "core/layout/api/LineLayoutAPIShim.h"
 #include "core/layout/line/InlineIterator.h"
 #include "core/layout/ng/layout_ng_block_flow.h"
@@ -238,6 +240,24 @@ void NGBlockNode::CopyFragmentDataToLayoutBox(
   NGPhysicalBoxFragment* fragment =
       toNGPhysicalBoxFragment(layout_result->PhysicalFragment().get());
 
+  if (layout_box_->style()->specifiesColumns()) {
+    LayoutBlockFlow* multicolContainer = toLayoutBlockFlow(layout_box_);
+    LayoutMultiColumnFlowThread* flow_thread =
+        multicolContainer->multiColumnFlowThread();
+    if (!flow_thread) {
+      flow_thread = LayoutMultiColumnFlowThread::createAnonymous(
+          layout_box_->document(), *layout_box_->style());
+      multicolContainer->addChild(flow_thread);
+      flow_thread->populate();
+      multicolContainer->ensureRareData().m_multiColumnFlowThread = flow_thread;
+    }
+
+    flow_thread->firstMultiColumnSet()->setWidth(fragment->Width());
+    flow_thread->firstMultiColumnSet()->setHeight(fragment->Height());
+    flow_thread->firstMultiColumnSet()->clearNeedsLayout();
+    flow_thread->validateColumnSets();
+    flow_thread->clearNeedsLayout();
+  }
   layout_box_->setWidth(fragment->Width());
   layout_box_->setHeight(fragment->Height());
   NGBoxStrut border_and_padding = ComputeBorders(constraint_space, Style()) +