views: use MD padding for combobox

ui/views/controls/combobox/combobox.cc

 // Copyright (c) 2012 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/controls/combobox/combobox.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 973 matching lines @@
   return gfx::Size(width, font_list.GetHeight());
 }
 
 PrefixSelector* Combobox::GetPrefixSelector() {
   if (!selector_)
     selector_.reset(new PrefixSelector(this, this));
   return selector_.get();
 }
 
 int Combobox::GetArrowContainerWidth() const {
+  const int kMdPaddingWidth = 8;
+  int arrow_pad = UseMd() ? kMdPaddingWidth
+                          : PlatformStyle::kComboboxNormalArrowPadding;
   int padding = style_ == STYLE_NORMAL
-                    ? PlatformStyle::kComboboxNormalArrowPadding * 2
+                    ? arrow_pad * 2
                     : kActionLeftPadding + kActionRightPadding;
   return ArrowSize().width() + padding;
 }
 
 }  // namespace views