[LayoutNG] Add NGLineBoxFragment

third_party/WebKit/Source/core/layout/ng/ng_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_box_fragment.h"
 
 #include "core/layout/ng/ng_macros.h"
 #include "core/layout/ng/ng_physical_box_fragment.h"
 
 namespace blink {
 
+LayoutUnit NGBoxFragment::InlineOverflow() const {
+  return writing_mode_ == kHorizontalTopBottom
+             ? toNGPhysicalBoxFragment(physical_fragment_)->WidthOverflow()
+             : toNGPhysicalBoxFragment(physical_fragment_)->HeightOverflow();
+}
+
+LayoutUnit NGBoxFragment::BlockOverflow() const {
+  return writing_mode_ == kHorizontalTopBottom
+             ? toNGPhysicalBoxFragment(physical_fragment_)->HeightOverflow()
+             : toNGPhysicalBoxFragment(physical_fragment_)->WidthOverflow();
+}
+
 const WTF::Optional<NGLogicalOffset>& NGBoxFragment::BfcOffset() const {
   WRITING_MODE_IGNORED(
       "Accessing BFC offset is allowed here because writing"
       "modes are irrelevant in this case.");
   return toNGPhysicalBoxFragment(physical_fragment_)->BfcOffset();
 }
 
 const NGMarginStrut& NGBoxFragment::EndMarginStrut() const {
   WRITING_MODE_IGNORED(
       "Accessing the margin strut is fine here. Changing the writing mode"
       "establishes a new formatting context, for which a margin strut is"
       "never set for a fragment.");
   return toNGPhysicalBoxFragment(physical_fragment_)->EndMarginStrut();
 }
 
 }  // namespace blink