[LayoutNG] Implement LayoutBR/preserved newlines and tabs

third_party/WebKit/Source/platform/fonts/Font.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Holger Hans Peter Freyther
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 154 matching lines @@
   // Metrics that we query the FontFallbackList for.
   float SpaceWidth() const {
     DCHECK(PrimaryFont());
     return (PrimaryFont() ? PrimaryFont()->SpaceWidth() : 0) +
            GetFontDescription().LetterSpacing();
   }
   float TabWidth(const SimpleFontData*, const TabSize&, float position) const;
   float TabWidth(const TabSize& tab_size, float position) const {
     return TabWidth(PrimaryFont(), tab_size, position);
   }
+  LayoutUnit TabWidth(const TabSize&, LayoutUnit position) const;
 
   int EmphasisMarkAscent(const AtomicString&) const;
   int EmphasisMarkDescent(const AtomicString&) const;
   int EmphasisMarkHeight(const AtomicString&) const;
 
   // This may fail and return a nullptr in case the last resort font cannot be
   // loaded. This *should* not happen but in reality it does ever now and then
   // when, for whatever reason, the last resort font cannot be loaded.
   const SimpleFontData* PrimaryFont() const;
   const FontData* FontDataAt(unsigned) const;
@@ skipping 76 matching lines @@
   // advance an additional tab stop.
   if (distance_to_tab_stop < font_data->SpaceWidth() / 2)
     distance_to_tab_stop += base_tab_width;
 
   return distance_to_tab_stop;
 }
 
 }  // namespace blink
 
 #endif