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

chrome/browser/ui/views/harmony/chrome_typography.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_TYPOGRAPHY_H_
 #define CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_TYPOGRAPHY_H_
 
 #include "base/macros.h"
 #include "ui/views/style/typography.h"
 #include "ui/views/style/typography_provider.h"
 
+#if defined(USE_ASH)
+#include "ash/public/cpp/ash_typography.h"
+#endif
+
 enum ChromeTextContext {
+#if defined(USE_ASH)
+  CHROME_TEXT_CONTEXT_START = ash::ASH_TEXT_CONTEXT_END,
+#else
+  CHROME_TEXT_CONTEXT_START = views::style::VIEWS_TEXT_CONTEXT_END,
+#endif
+
   // Headline text. Usually 20pt. Never multi-line.
-  CONTEXT_HEADLINE = views::style::VIEWS_TEXT_CONTEXT_END,
+  CONTEXT_HEADLINE = CHROME_TEXT_CONTEXT_START,
 
   // "Body 1". Usually 13pt.
   CONTEXT_BODY_TEXT_LARGE,
 
   // "Body 2". Usually 12pt.
   CONTEXT_BODY_TEXT_SMALL,
 
   // ResourceBundle::SmallFont (11 pt). There is no equivalent in the Harmony
   // spec, so new code should not be using this. It is only provided to avoid
   // changing existing UI and it will eventually be removed.
   CONTEXT_DEPRECATED_SMALL,
 };
 
 enum ChromeTextStyle {
+  CHROME_TEXT_STYLE_START = views::style::VIEWS_TEXT_STYLE_END,
+
   // Secondary text. May be lighter than views::style::PRIMARY.
-  STYLE_SECONDARY = views::style::VIEWS_TEXT_STYLE_END,
+  STYLE_SECONDARY = CHROME_TEXT_STYLE_START,
 
   // "Hint" text, usually a line that gives context to something more important.
   STYLE_HINT,
 
   // A solid shade of red.
   STYLE_RED,
 
   // A solid shade of green.
   STYLE_GREEN,
 
   // Used to draw attention to a section of body text such as an extension name
   // or hostname.
   STYLE_EMPHASIZED,
 };
 
 // TypographyProvider that provides pre-Harmony fonts in Chrome.
 class LegacyTypographyProvider : public views::DefaultTypographyProvider {
  public:
   LegacyTypographyProvider() = default;
 
   // DefaultTypographyProvider:
   const gfx::FontList& GetFont(int text_context, int text_style) const override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LegacyTypographyProvider);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_HARMONY_CHROME_TYPOGRAPHY_H_