"Bootstrap" a toolkit-views Typography spec.

ui/views/style/typography.h

Index: ui/views/style/typography.h
diff --git a/ui/views/style/typography.h b/ui/views/style/typography.h
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+// 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 UI_VIEWS_STYLE_TYPOGRAPHY_H_
+#define UI_VIEWS_STYLE_TYPOGRAPHY_H_
+
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/views/views_export.h"
+
+namespace gfx {
+class FontList;
+}
+
+namespace views {
+namespace style {
+
+// Where a piece of text appears in the UI. This influences size and weight, but
+// typically not style or color.
+enum TextContext {
+  // Embedders can extend this enum with additional values that are understood
+  // by the TypographyProvider offered by their ViewsDelegate. Embedders define
+  // enum values from VIEWS_TEXT_CONTEXT_END. Values named beginning with
+  // "CONTEXT_" represent the actual TextContexts: the rest are markers.
+  VIEWS_TEXT_CONTEXT_START = 0,
+
+  // A title for a dialog window. Usually 15pt. Multi-line OK.
+  CONTEXT_DIALOG_TITLE = VIEWS_TEXT_CONTEXT_START,
+
+  // Text to label a control, usually next to it. "Body 2". Usually 12pt.
+  CONTEXT_LABEL,
+
+  // An editable text field. Usually matches CONTROL_LABEL.
+  CONTEXT_TEXTFIELD,
+
+  // Text that appears on a button control. Usually 12pt.
+  CONTEXT_BUTTON,
+
+  // Embedders must start TextContext enum values from this value.
+  VIEWS_TEXT_CONTEXT_END,
+
+  // All TextContext enum values must be below this value.
+  TEXT_CONTEXT_MAX = 0x1000
+};
+
+// How a piece of text should be presented. This influences color and style, but
+// typically not size.
+enum TextStyle {
+  // TextStyle enum values must always be greater than any TextContext value.
+  // This allows the code to verify at runtime that arguments of the two types
+  // have not been swapped.
+  VIEWS_TEXT_STYLE_START = TEXT_CONTEXT_MAX,
+
+  // Primary text: solid black, normal weight. Converts to DISABLED in some
+  // contexts (e.g. BUTTON_TEXT, FIELD).
+  STYLE_PRIMARY = VIEWS_TEXT_STYLE_START,

[sky, 2017/03/20 16:33:11]

Did you consider STYLE_ENABLED? I like that better as 'primary' implies there is
a secondary. 'enabled' also better aligns with 'disabled'.

[Peter Kasting, 2017/03/20 20:00:34]

There is a "secondary"; it's over on the Chrome side.

[tapted, 2017/03/20 22:31:42]

There is that :). I also think ENABLED is too specific here -- DISABLED only
applies to text contexts where it makes sense for it to have a disabled state.
But PRIMARY applies to any text context -- it's not necessarily the inverse of
DISABLED.

E.g., in theory, a UI might toggle between PRIMARY/DISABLED or
SECONDARY/DISABLED or HINT/DISABLED -- and we can get rid of lot of Label:: data
members for "disabled" colors this way since the "disabled" state is orthogonal
to the "style". That is, calling View::SetEnabled(false) on a Label doesn't need
to change its *style* - we just override its current style with DISABLED until
something does SetEnabled(true).

+
+  // Disabled "greyed out" text.
+  STYLE_DISABLED,
+
+  // The style used for links. Usually a solid shade of blue.
+  STYLE_LINK,
+
+  // Active tab in a tabbed pane.
+  STYLE_TAB_ACTIVE,
+
+  // Hovered tab in a tabbed pane.
+  STYLE_TAB_HOVERED,
+
+  // Inactive tab in a tabbed pane.
+  STYLE_TAB_INACTIVE,
+
+  // Embedders must start TextStyle enum values from here.
+  VIEWS_TEXT_STYLE_END
+};
+
+// Helpers to obtain font properties from the TypographyProvider given by the
+// current ViewsDelegate. |context| can be an enum value from TextContext, or a
+// value understood by the embedder's TypographyProvider. Similarly,
+// |text_style| corresponds to TextStyle.
+VIEWS_EXPORT const gfx::FontList& GetFont(int text_context, int text_style);
+VIEWS_EXPORT SkColor GetColor(int text_context, int text_style);
+VIEWS_EXPORT int GetLineHeight(int text_context, int text_style);
+
+}  // namespace style
+}  // namespace views
+
+#endif  // UI_VIEWS_STYLE_TYPOGRAPHY_H_