[LayoutNG] Initial support for multicol, introducing NGBlockBreakToken.

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ng/ng_physical_box_fragment.h"
 
 namespace blink {
 
 NGPhysicalBoxFragment::NGPhysicalBoxFragment(
     NGPhysicalSize size,
     NGPhysicalSize overflow,
     HeapVector<Member<const NGPhysicalFragment>>& children,
     HeapLinkedHashSet<WeakMember<NGBlockNode>>& out_of_flow_descendants,
     Vector<NGStaticPosition>& out_of_flow_positions,
-    NGMarginStrut margin_strut)
+    NGMarginStrut margin_strut,
+    NGBreakToken* break_token)
     : NGPhysicalFragment(size,
                          overflow,
                          kFragmentBox,
                          out_of_flow_descendants,
-                         out_of_flow_positions),
+                         out_of_flow_positions,
+                         break_token),
       margin_strut_(margin_strut) {
   children_.swap(children);
 }
 
 DEFINE_TRACE_AFTER_DISPATCH(NGPhysicalBoxFragment) {
   visitor->trace(children_);
   NGPhysicalFragment::traceAfterDispatch(visitor);
 }
 
 }  // namespace blink