Use views::style for buttons, bootstrap ash_typography to do so.

chrome/browser/ui/views/harmony/layout_provider_unittest.cc

 // Copyright 2017 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 "base/strings/utf_string_conversions.h"
 #include "chrome/browser/ui/views/harmony/chrome_layout_provider.h"
 #include "chrome/browser/ui/views/harmony/chrome_typography.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/default_style.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 261 matching lines @@
     const gfx::FontList& font = views::style::GetFont(increase.context, kStyle);
     int line_spacing = views::style::GetLineHeight(increase.context, kStyle);
     EXPECT_GE(increase.max, line_spacing - font.GetHeight());
     EXPECT_LE(increase.min, line_spacing - font.GetHeight());
   }
 
   // Buttons should specify zero line height (i.e. use the font's height) so
   // buttons have flexibility to configure their own spacing.
   EXPECT_EQ(0,
             views::style::GetLineHeight(views::style::CONTEXT_BUTTON, kStyle));
+  EXPECT_EQ(
+      0, views::style::GetLineHeight(views::style::CONTEXT_BUTTON_MD, kStyle));
 }
 
 // Ensure that line heights reported in a default bot configuration match the
 // Harmony spec. This test will only run if it detects that the current machine
 // has the default OS configuration.
 TEST(LayoutProviderTest, ExplicitTypographyLineHeight) {
   ui::test::MaterialDesignControllerTestAPI md_test_api(
       ui::MaterialDesignController::MATERIAL_NORMAL);
   md_test_api.SetSecondaryUiMaterial(true);
 
@@ skipping 36 matching lines @@
   constexpr int kStyledLabelWidth = 200;  // Enough to avoid wrapping.
   styled_label.SizeToFit(kStyledLabelWidth);
   EXPECT_EQ(kBodyLineHeight, styled_label.height());
 
   // Adding a link should not change the size.
   styled_label.AddStyleRange(
       gfx::Range(0, 2), views::StyledLabel::RangeStyleInfo::CreateForLink());
   styled_label.SizeToFit(kStyledLabelWidth);
   EXPECT_EQ(kBodyLineHeight, styled_label.height());
 }