MacViews: draw Mac combobox arrows

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 738 matching lines @@
   gfx::Rect arrow_bounds(arrow_x,
                          height() / 2 - arrow_size.height() / 2,
                          arrow_size.width(),
                          arrow_size.height());
   AdjustBoundsForRTLUI(&arrow_bounds);
 
   // TODO(estade): hack alert! Remove this direct call into CommonTheme. For now
   // STYLE_ACTION isn't properly themed so we have to override the NativeTheme
   // behavior. See crbug.com/384071
   if (style_ == STYLE_ACTION) {
     ui::CommonThemePaintComboboxArrow(canvas->sk_canvas(), arrow_bounds);

[tapted, 2016/03/29 04:16:36]

I think this is the only caller now, and the method is pretty similar to what's
below.  Except I guess the Mac arrows wouldn't be appropriate for STYLE_ACTION,
(i.e. supposing we do decide to have STYLE_ACTION comboboxes appear on Chrome's
Mac UI, which is unlikely).

Can we remove this method from ui:: by passing `style_` into
PlatformStyle::CreateComboboxArrow? Then have mac use the raster asset for
ACTION_STYLE

Merging the logic here is probably necessary anyway, since |arrow_bounds| is
initialised with Combobox::ArrowSize() which won't be the size of the triangle

[Elly Fong-Jones, 2016/04/04 17:09:55]

Done.

   } else {
-    ui::NativeTheme::ExtraParams ignored;
-    GetNativeTheme()->Paint(canvas->sk_canvas(),
-                            ui::NativeTheme::kComboboxArrow,
-                            ui::NativeTheme::kNormal,
-                            arrow_bounds,
-                            ignored);
+    gfx::ImageSkia arrow_image = PlatformStyle::CreateComboboxArrow(
+        enabled());
+    gfx::Rect image_bounds(arrow_bounds);
+    image_bounds.Inset((arrow_bounds.width() - arrow_image.width()) / 2,

[tapted, 2016/03/29 04:16:36]

I think this is the same as

image_bounds.ClampToCenteredSize(arrow_image.size());

But shouldn't arrow_bounds.size() and arrow_image.size() be the same already,
since Combobox::ArrowSize() is now derived the same way

[Elly Fong-Jones, 2016/04/04 17:09:55]

Done.

+                       (arrow_bounds.height() - arrow_image.height()) / 2);
+    canvas->DrawImageInt(arrow_image, image_bounds.x(), image_bounds.y());
   }
 }
 
 void Combobox::PaintButtons(gfx::Canvas* canvas) {
   DCHECK(style_ == STYLE_ACTION);
 
   gfx::ScopedCanvas scoped_canvas(canvas);
   if (base::i18n::IsRTL()) {
     canvas->Translate(gfx::Vector2d(width(), 0));
     canvas->Scale(-1, 1);
@@ skipping 121 matching lines @@
     case STYLE_NORMAL:
       return kDisclosureArrowRightPadding;
     case STYLE_ACTION:
       return kDisclosureArrowButtonRightPadding;
   }
   NOTREACHED();
   return 0;
 }
 
 gfx::Size Combobox::ArrowSize() const {
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
-  // TODO(estade): hack alert! This should always use GetNativeTheme(). For now
-  // STYLE_ACTION isn't properly themed so we have to override the NativeTheme
-  // behavior. See crbug.com/384071
-  const ui::NativeTheme* native_theme_for_arrow =
-      style_ == STYLE_ACTION ? ui::NativeThemeAura::instance()
-                             : GetNativeTheme();
-#else
-  const ui::NativeTheme* native_theme_for_arrow = GetNativeTheme();
-#endif
-
-  ui::NativeTheme::ExtraParams ignored;
-  return native_theme_for_arrow->GetPartSize(ui::NativeTheme::kComboboxArrow,
-                                             ui::NativeTheme::kNormal,
-                                             ignored);
+  return PlatformStyle::CreateComboboxArrow(enabled()).size();
 }
 
 gfx::Size Combobox::GetContentSize() const {
   const gfx::FontList& font_list = GetFontList();
 
   int width = 0;
   for (int i = 0; i < model()->GetItemCount(); ++i) {
     if (model_->IsItemSeparatorAt(i))
       continue;
 
     if (style_ != STYLE_ACTION || i == selected_index_) {
       width = std::max(
           width,
           gfx::GetStringWidth(menu_model_adapter_->GetLabelAt(i), font_list));
     }
   }
   return gfx::Size(width, font_list.GetHeight());
 }
 
 PrefixSelector* Combobox::GetPrefixSelector() {
   if (!selector_)
     selector_.reset(new PrefixSelector(this));
   return selector_.get();
 }
 
 }  // namespace views