[LayoutNG] UpdateMargins is no longer needed by LayoutNGBlockFlow

After CL 827548, margins are always copied to Legacy.
Additional copy in LayoutNGBlockFlow is no longer needed.
Ian says so.

Bug: 740993
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: If1aee4b15a966d58bd62f66190fdf00f035ed0b4
Reviewed-on: https://chromium-review.googlesource.com/830474Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Aleks Totic <atotic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524538}

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

@@ -38,14 +38,6 @@ void LayoutNGBlockFlow::UpdateBlockLayout(bool relayout_children) {
   scoped_refptr<NGLayoutResult> result =
       NGBlockNode(this).Layout(*constraint_space);
 
-  // We need to update our margins as these are calculated once and stored in
-  // LayoutBox::margin_box_outsets_. Typically this happens within
-  // UpdateLogicalWidth and UpdateLogicalHeight.
-  //
-  // This primarily fixes cases where we are embedded inside another layout,
-  // for example LayoutView, LayoutFlexibleBox, etc.
-  UpdateMargins(*constraint_space);
-
   for (NGOutOfFlowPositionedDescendant descendant :
        result->OutOfFlowPositionedDescendants())
     descendant.node.UseOldOutOfFlowPositioning();

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

@@ -157,12 +157,6 @@ void LayoutNGMixin<Base>::Paint(const PaintInfo& paint_info,
     LayoutBlockFlow::Paint(paint_info, paint_offset);
 }
 
-template <typename Base>
-void LayoutNGMixin<Base>::UpdateMargins(
-    const NGConstraintSpace& constraint_space) {
-  Base::SetMargin(ComputePhysicalMargins(constraint_space, Base::StyleRef()));
-}
-
 template <typename Base>
 bool LayoutNGMixin<Base>::NodeAtPoint(
     HitTestResult& result,

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

@@ -75,8 +75,6 @@ class CORE_TEMPLATE_CLASS_EXPORT LayoutNGMixin : public Base {
 
   const NGBaseline* FragmentBaseline(NGBaselineAlgorithmType) const;
 
-  void UpdateMargins(const NGConstraintSpace&);
-
   std::unique_ptr<NGInlineNodeData> ng_inline_node_data_;
 
   scoped_refptr<NGLayoutResult> cached_result_;