MacViews: draw combobox arrow backgrounds

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 382c6db3ce101d65d28c70c697fb281a6a0fe20c..62a3fe67d9d3a7a7e106dca463882064bc28af95 100644
--- a/ui/views/controls/combobox/combobox.cc
+++ b/ui/views/controls/combobox/combobox.cc
@@ -625,6 +625,9 @@ void Combobox::OnPaint(gfx::Canvas* canvas) {
   switch (style_) {
     case STYLE_NORMAL: {
       OnPaintBackground(canvas);
+      // Painting the arrow background needs to happen before PaintText applies
+      // a clip rect to |canvas| so the background can touch the border.
+      PaintArrowBackground(canvas);
       PaintText(canvas);
       OnPaintBorder(canvas);
       break;
@@ -713,7 +716,8 @@ void Combobox::PaintText(gfx::Canvas* canvas) {
   int y = insets.top();
   int text_height = height() - insets.height();
   SkColor text_color = GetNativeTheme()->GetSystemColor(
-      ui::NativeTheme::kColorId_LabelEnabledColor);
+      enabled() ? ui::NativeTheme::kColorId_LabelEnabledColor :
+                  ui::NativeTheme::kColorId_LabelDisabledColor);
 
   DCHECK_GE(selected_index_, 0);
   DCHECK_LT(selected_index_, model()->GetItemCount());
@@ -813,6 +817,29 @@ void Combobox::PaintButtons(gfx::Canvas* canvas) {
   }
 }
 
+void Combobox::PaintArrowBackground(gfx::Canvas* canvas) {
+  gfx::ScopedCanvas scoped_canvas(canvas);

[tapted, 2016/03/22 11:20:26]

This is a lot of code for something Mac-specific - I think combobox doesn't have
a background set via View::set_background(..). A Background::Paint(..) override
really feels like the right place for this -- something created by PlatformStyle
(default implementation returns null).

Background::Paint(..) takes in a views::View* -- we can DCHECK
view->GetClassName() == Combobox::kViewClassName and cast it to get the arrow
size.

(also there's Background::CreateVerticalMultiColorGradientBackground but it
probably won't handle the corners)

Then, I'm uncertain where the line between the Background override and
NativeTheme should be. Since it's mac-specific and not actually reaching into
anything from the native OS, I think we should not modify NativeTheme.

I like GetButtonBackgroundShader though. I'm just not sure if it belongs on
NativeThemeMac or in platform_style_mac.h - let's ask sky

[Elly Fong-Jones, 2016/03/22 22:05:10]

Done.

+
+  if (base::i18n::IsRTL()) {
+    canvas->Translate(gfx::Vector2d(width(), 0));
+    canvas->Scale(-1, 1);
+  }
+
+  gfx::Rect bounds = GetLocalBounds();
+  gfx::Size arrow_size = ArrowSize();
+  int disclosure_arrow_offset = width() - arrow_size.width() -
+      GetDisclosureArrowLeftPadding() - GetDisclosureArrowRightPadding();
+  bounds.Inset(disclosure_arrow_offset, 0, 0, 0);
+
+  ui::NativeTheme::State state =
+      HasFocus() ? ui::NativeTheme::kHovered : ui::NativeTheme::kNormal;
+  GetNativeTheme()->Paint(canvas->sk_canvas(),
+                          ui::NativeTheme::kComboboxArrowBackground,
+                          state,
+                          bounds,
+                          ui::NativeTheme::ExtraParams());
+}
+
 void Combobox::ShowDropDownMenu(ui::MenuSourceType source_type) {
   gfx::Rect lb = GetLocalBounds();
   gfx::Point menu_position(lb.origin());