MacViews: draw Mac combobox arrows

ui/views/controls/combobox/combobox.cc

Index: ui/views/controls/combobox/combobox.cc
diff --git a/ui/views/controls/combobox/combobox.cc b/ui/views/controls/combobox/combobox.cc
index 88cd6efcd828144ff173e548ec2d958d3ce94dbf..c7d745a490ba2558c80443d52068bd05ddb001ad 100644
--- a/ui/views/controls/combobox/combobox.cc
+++ b/ui/views/controls/combobox/combobox.cc
@@ -758,12 +758,12 @@ void Combobox::PaintText(gfx::Canvas* canvas) {
   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());
   }
 }
 
@@ -905,21 +905,7 @@ int Combobox::GetDisclosureArrowRightPadding() const {
 }
 
 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 {