macviews: honor system control tint setting

ui/native_theme/native_theme_mac.h

 // Copyright (c) 2013 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_NATIVE_THEME_NATIVE_THEME_MAC_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_MAC_H_
 
 #include "base/macros.h"
 #include "ui/native_theme/native_theme_base.h"
 #include "ui/native_theme/native_theme_export.h"
@@ skipping 11 matching lines @@
   enum class ButtonBackgroundType {
     DISABLED,
     HIGHLIGHTED,
     NORMAL,
     PRESSED,
     COUNT
   };
 
   static NativeThemeMac* instance();
 
+  // Adjusts an SkColor based on the current system control tint. For example,
+  // if the current tint is "graphite", this function maps the provided value to
+  // an appropriate gray.
+  static SkColor ApplySystemControlTint(SkColor color);
+
   // Overridden from NativeTheme:
   SkColor GetSystemColor(ColorId color_id) const override;
 
   // Overridden from NativeThemeBase:
   void PaintMenuPopupBackground(
       SkCanvas* canvas,
       const gfx::Size& size,
       const MenuBackgroundExtraParams& menu_background) const override;
   void PaintMenuItemBackground(
       SkCanvas* canvas,
@@ skipping 24 matching lines @@
  private:
   NativeThemeMac();
   ~NativeThemeMac() override;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeMac);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_MAC_H_