views: refactor away PlatformStyle::BackgroundColorForMdButton

ui/views/style/platform_style.h

 // Copyright 2015 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_PLATFORM_STYLE_H_
 #define UI_VIEWS_STYLE_PLATFORM_STYLE_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 70 matching lines @@
   // Returns the current text color for the current button state.
   static SkColor TextColorForButton(const ButtonColorByState& color_by_state,
                                     const LabelButton& button);
 
   // Applies platform styles to |label| and fills |color_by_state| with the text
   // colors for normal, pressed, hovered, and disabled states, if the colors for
   // Button::STYLE_BUTTON buttons differ from those provided by ui::NativeTheme.
   static void ApplyLabelButtonTextStyle(Label* label,
                                         ButtonColorByState* color_by_state);
 
-  // Returns the background color that should be used for an MdTextButton or
-  // other MD controls when in the given state.
-  static SkColor BackgroundColorForMdButton(SkColor color,
-                                            Button::ButtonState state);
-
   // Applies the current system theme to the default border created by |button|.
   static std::unique_ptr<Border> CreateThemedLabelButtonBorder(
       LabelButton* button);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformStyle);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_STYLE_PLATFORM_STYLE_H_