views combobox: use MD padding on Mac in MD mode

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 389 matching lines @@
       weak_ptr_factory_(this) {
   ModelChanged();
 #if defined(OS_MACOSX)
   SetFocusBehavior(FocusBehavior::ACCESSIBLE_ONLY);
 #else
   SetFocusBehavior(FocusBehavior::ALWAYS);
 #endif
 
   UpdateBorder();
   // set_background() takes ownership but takes a raw pointer.
-  std::unique_ptr<Background> b =
-      PlatformStyle::CreateComboboxBackground(GetArrowContainerWidth());
-  set_background(b.release());
+  if (!UseMd()) {
+    std::unique_ptr<Background> b =
+        PlatformStyle::CreateComboboxBackground(GetArrowContainerWidth());
+    set_background(b.release());
+  }
 
   // Initialize the button images.
   Button::ButtonState button_states[] = {
     Button::STATE_DISABLED,
     Button::STATE_NORMAL,
     Button::STATE_HOVERED,
     Button::STATE_PRESSED,
   };
   for (int i = 0; i < 2; i++) {
     for (size_t state_index = 0; state_index < arraysize(button_states);
@@ skipping 358 matching lines @@
 
   int disclosure_arrow_offset = width() - GetArrowContainerWidth();
 
   const gfx::FontList& font_list = Combobox::GetFontList();
   int text_width = gfx::GetStringWidth(text, font_list);
   if ((text_width + insets.width()) > disclosure_arrow_offset)
     text_width = disclosure_arrow_offset - insets.width();
 
   gfx::Rect text_bounds(x, y, text_width, text_height);
   AdjustBoundsForRTLUI(&text_bounds);
+  // TODO(ellyjones): This doesn't seem right. There's no particular reason why
+  // the text should need the rectangle underneath it filled first while none of
+  // the other drawn things need that. Also, drawing over with
+  // SK_ColorTRANSPARENT doesn't seem to suffice. Why?
+  if (UseMd())
+    canvas->FillRect(text_bounds, SK_ColorWHITE);
   canvas->DrawStringRect(text, font_list, text_color, text_bounds);
 
   gfx::Rect arrow_bounds(disclosure_arrow_offset, 0, GetArrowContainerWidth(),
                          height());
   arrow_bounds =
       PositionArrowWithinContainer(arrow_bounds, ArrowSize(), style_);
   AdjustBoundsForRTLUI(&arrow_bounds);
 
   if (UseMd()) {
     // Since this is a core piece of UI and vector icons don't handle fractional
@@ skipping 160 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;

[Evan Stade, 2016/09/07 17:24:43]

this change seems fine

+  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