Support underline on Linux again.

ui/gfx/font_list_unittest.cc

 // Copyright (c) 2012 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 "ui/gfx/font_list.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 242 matching lines @@
   fonts.push_back(Font("Courier New", 8));
   FontList font_list = FontList(fonts);
 
   FontList derived = font_list.Derive(5, Font::ITALIC, Font::Weight::BOLD);
   const std::vector<Font>& derived_fonts = derived.GetFonts();
 
   EXPECT_EQ(2U, derived_fonts.size());
   EXPECT_EQ("Arial|13|italic|bold", FontToString(derived_fonts[0]));
   EXPECT_EQ("Courier New|13|italic|bold", FontToString(derived_fonts[1]));
 
-  // TODO(mboc): Linux has never supported UNDERLINE. Fix this if possible.
-#if !defined(OS_LINUX)
   derived = font_list.Derive(5, Font::UNDERLINE, Font::Weight::BOLD);
   const std::vector<Font>& underline_fonts = derived.GetFonts();
 
   EXPECT_EQ(2U, underline_fonts.size());
   EXPECT_EQ("Arial|13|underline|bold", FontToString(underline_fonts[0]));
   EXPECT_EQ("Courier New|13|underline|bold", FontToString(underline_fonts[1]));
-#endif
 }
 
 // TODO(489354): Enable this on android.
 #if defined(OS_ANDROID)
 #define MAYBE_Fonts_DeriveWithSizeDelta DISABLED_Fonts_DeriveWithSizeDelta
 #else
 #define MAYBE_Fonts_DeriveWithSizeDelta Fonts_DeriveWithSizeDelta
 #endif
 TEST(FontListTest, MAYBE_Fonts_DeriveWithSizeDelta) {
   std::vector<Font> fonts;
@@ skipping 69 matching lines @@
 
   // A larger upper bound should not change the height of the font list.
   const int height_2 = font_list.GetHeight() + 5;
   FontList derived_2 = font_list.DeriveWithHeightUpperBound(height_2);
   EXPECT_LE(derived_2.GetHeight(), height_2);
   EXPECT_EQ(font_list.GetHeight(), derived_2.GetHeight());
   EXPECT_EQ(font_list.GetFontSize(), derived_2.GetFontSize());
 }
 
 }  // namespace gfx