Harmony - Use FocusableBorder for comboboxes on Mac

ui/views/style/platform_style_mac.mm

 // 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.
 
 #include "ui/views/style/platform_style.h"
 
 #include "base/memory/ptr_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/paint_vector_icon.h"
@@ skipping 35 matching lines @@
                  : gfx::VectorIconId::COMBOBOX_ARROW_MAC_DISABLED,
       kComboboxArrowWidth, SK_ColorBLACK);
 }
 
 // static
 std::unique_ptr<FocusableBorder> PlatformStyle::CreateComboboxBorder() {
   return base::WrapUnique(new FocusableRoundedBorder);
 }
 
 // static
-std::unique_ptr<Background> PlatformStyle::CreateComboboxBackground(
-    int shoulder_width) {
-  return base::MakeUnique<ComboboxBackgroundMac>(shoulder_width);
-}
-
-// static
 std::unique_ptr<ScrollBar> PlatformStyle::CreateScrollBar(bool is_horizontal) {
   return base::MakeUnique<CocoaScrollBar>(is_horizontal);
 }
 
 // static
 SkColor PlatformStyle::TextColorForButton(
     const ButtonColorByState& color_by_state,
     const LabelButton& button) {
   Button::ButtonState state = button.state();
   if (button.style() == Button::STYLE_BUTTON && button.is_default()) {
@@ skipping 11 matching lines @@
   ButtonColorByState& colors = *color_by_state;
   colors[Button::STATE_PRESSED] = SK_ColorWHITE;
 }
 
 // static
 void PlatformStyle::OnTextfieldKeypressUnhandled() {
   NSBeep();
 }
 
 }  // namespace views