Fix multicol abspos DCHECKs

Bug: 740993
Change-Id: I9bc0340fcf8609702187a79f9d7ed07a5c781e4d
Reviewed-on: https://chromium-review.googlesource.com/764042
Commit-Queue: Aleks Totic <atotic@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516021}

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

@@ -113,7 +113,7 @@ scoped_refptr<NGLayoutResult> NGColumnLayoutAlgorithm::Layout() {
         ToNGPhysicalBoxFragment(result->PhysicalFragment().get()));
 
     NGLogicalOffset logical_offset(column_inline_offset, column_block_offset);
-    container_builder_.AddChild(column, logical_offset);
+    container_builder_.AddChild(result, logical_offset);
 
     intrinsic_block_size = std::max(
         intrinsic_block_size,

third_party/WebKit/Source/core/layout/ng/ng_container_fragment_builder.h

@@ -51,6 +51,9 @@ class CORE_EXPORT NGContainerFragmentBuilder : public NGBaseFragmentBuilder {
 
   virtual NGContainerFragmentBuilder& AddChild(scoped_refptr<NGLayoutResult>,
                                                const NGLogicalOffset&);
+
+  // This version of AddChild will not propagate floats/out_of_flow.
+  // Use the AddChild(NGLayoutResult) variant if NGLayoutResult is available.
   virtual NGContainerFragmentBuilder& AddChild(
       scoped_refptr<NGPhysicalFragment>,
       const NGLogicalOffset&);

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

@@ -56,7 +56,7 @@ scoped_refptr<NGLayoutResult> NGPageLayoutAlgorithm::Layout() {
     scoped_refptr<NGPhysicalBoxFragment> page(
         ToNGPhysicalBoxFragment(result->PhysicalFragment().get()));
 
-    container_builder_.AddChild(page, page_offset);
+    container_builder_.AddChild(result, page_offset);
 
     NGBoxFragment logical_fragment(writing_mode, *page);
     intrinsic_block_size =