MacViews: draw combobox arrow backgrounds

ui/views/style/mac/combobox_background_mac.cc

+// Copyright 2016 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/style/mac/combobox_background_mac.h"
+
+#include "third_party/skia/include/core/SkPath.h"
+#include "third_party/skia/include/core/SkRRect.h"
+#include "ui/gfx/canvas.h"
+#include "ui/native_theme/native_theme_mac.h"
+#include "ui/views/controls/combobox/combobox.h"
+#include "ui/views/view.h"
+
+namespace views {
+
+ComboboxBackgroundMac::ComboboxBackgroundMac() {}
+
+ComboboxBackgroundMac::~ComboboxBackgroundMac() {}
+
+void ComboboxBackgroundMac::Paint(gfx::Canvas* canvas, View* view) const {
+  DCHECK_EQ(view->GetClassName(), Combobox::kViewClassName);
+  Combobox* combobox = static_cast<Combobox*>(view);
+
+  gfx::RectF bounds(combobox->GetLocalBounds());
+  // Inset the left side far enough to draw only the arrow button, and inset the
+  // other three sides by half a pixel so the edge of the background doesn't
+  // paint outside the border.
+  bounds.Inset(bounds.width() - combobox->GetArrowButtonWidth(), 0.5, 0.5, 0.5);
+
+  ui::NativeTheme::State state = ui::NativeTheme::kNormal;
+  if (!combobox->enabled())
+    state = ui::NativeTheme::kDisabled;
+
+  skia::RefPtr<SkShader> shader =
+      ui::NativeThemeMac::GetButtonBackgroundShader(
+          state,
+          bounds.height());
+  SkPaint paint;
+  paint.setShader(shader.get());
+  paint.setStyle(SkPaint::kFill_Style);
+  paint.setAntiAlias(true);
+
+  SkPoint no_curve = SkPoint::Make(0, 0);
+  SkPoint curve = SkPoint::Make(
+      ui::NativeThemeMac::kComboboxCornerRadius,
+      ui::NativeThemeMac::kComboboxCornerRadius);
+  SkVector curves[4] = { no_curve, curve, curve, no_curve };
+
+  SkRRect fill_rect;
+  fill_rect.setRectRadii(gfx::RectFToSkRect(bounds), curves);
+
+  SkPath path;
+  path.addRRect(fill_rect);
+
+  canvas->DrawPath(path, paint);
+}
+
+}  // namespace views