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

ash/public/cpp/ash_typography.h

Index: ash/public/cpp/ash_typography.h
diff --git a/ash/public/cpp/ash_typography.h b/ash/public/cpp/ash_typography.h
new file mode 100644
index 0000000000000000000000000000000000000000..e56a192276444614c8941c2b6c9323aec5b3097a
--- /dev/null
+++ b/ash/public/cpp/ash_typography.h
@@ -0,0 +1,35 @@
+// 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 ASH_PUBLIC_CPP_ASH_TYPOGRAPHY_H_

[tapted, 2017/05/15 23:02:33]

I couldn't decide whether to drop the "ash_" and just call this typography.h -
(the ash_ prefix is consistent with chrome_typography.h, but seems to diverge a
bit from other things in ash/public/cpp).

[Peter Kasting, 2017/05/15 23:29:47]

You could solve this inconsistency by dropping it from both :)

+#define ASH_PUBLIC_CPP_ASH_TYPOGRAPHY_H_
+
+#include "ash/public/cpp/ash_public_export.h"
+#include "ui/gfx/font.h"
+#include "ui/views/style/typography.h"
+
+namespace ash {
+
+enum AshTextContext {
+  ASH_TEXT_CONTEXT_START = views::style::VIEWS_TEXT_CONTEXT_END,
+
+  // A button that appears in the launcher's status area.
+  CONTEXT_LAUNCHER_BUTTON = ASH_TEXT_CONTEXT_START,
+
+  // Buttons and labels that appear in the fullscreen toast overlay UI.
+  CONTEXT_TOAST_OVERLAY,
+
+  ASH_TEXT_CONTEXT_END
+};
+
+// Sets the |size_delta| and |font_weight| for ash-specific text contexts.
+// Values are only set for contexts specific to ash.
+void ASH_PUBLIC_EXPORT ApplyAshFontStyles(int context,
+                                          int style,
+                                          int* size_delta,
+                                          gfx::Font::Weight* font_weight);
+
+}  // namespace ash
+
+#endif  // ASH_PUBLIC_CPP_ASH_TYPOGRAPHY_H_