[LayoutNG] Implement 'text-align-last'

third_party/WebKit/Source/core/style/ComputedStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 1405 matching lines @@
   DEFINE_STATIC_LOCAL(AtomicString, hyphen_minus_string,
                       (&kHyphenMinusCharacter, 1));
   DEFINE_STATIC_LOCAL(AtomicString, hyphen_string, (&kHyphenCharacter, 1));
   const SimpleFontData* primary_font = GetFont().PrimaryFont();
   DCHECK(primary_font);
   return primary_font && primary_font->GlyphForCharacter(kHyphenCharacter)
              ? hyphen_string
              : hyphen_minus_string;
 }
 
+ETextAlign ComputedStyle::GetTextAlign(bool is_last_line) const {
+  if (!is_last_line)
+    return GetTextAlign();
+
+  // When this is the last line of a block, or the line ends with a forced line
+  // break.
+  // https://drafts.csswg.org/css-text-3/#propdef-text-align-last
+  switch (TextAlignLast()) {
+    case ETextAlignLast::kStart:
+      return ETextAlign::kStart;
+    case ETextAlignLast::kEnd:
+      return ETextAlign::kEnd;
+    case ETextAlignLast::kLeft:
+      return ETextAlign::kLeft;
+    case ETextAlignLast::kRight:
+      return ETextAlign::kRight;
+    case ETextAlignLast::kCenter:
+      return ETextAlign::kCenter;
+    case ETextAlignLast::kJustify:
+      return ETextAlign::kJustify;
+    case ETextAlignLast::kAuto:
+      ETextAlign text_align = GetTextAlign();
+      if (text_align == ETextAlign::kJustify)
+        return ETextAlign::kStart;
+      return text_align;
+  }
+  NOTREACHED();
+  return GetTextAlign();
+}
+
 const AtomicString& ComputedStyle::TextEmphasisMarkString() const {
   switch (GetTextEmphasisMark()) {
     case TextEmphasisMark::kNone:
       return g_null_atom;
     case TextEmphasisMark::kCustom:
       return TextEmphasisCustomMark();
     case TextEmphasisMark::kDot: {
       DEFINE_STATIC_LOCAL(AtomicString, filled_dot_string,
                           (&kBulletCharacter, 1));
       DEFINE_STATIC_LOCAL(AtomicString, open_dot_string,
@@ skipping 915 matching lines @@
     if (value < 0)
       fvalue -= 0.5f;
     else
       fvalue += 0.5f;
   }
 
   return RoundForImpreciseConversion<int>(fvalue / zoom_factor);
 }
 
 }  // namespace blink