Views: Added default constructability to Slider

Updated Slider to be default constructable. Cleaned up some calling
code.

Bug: 1108460
Change-Id: I03b91286288322c2709e9ace2d0196dbc04ff230
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2313496Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Commit-Queue: Thomas Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791234}

ash/system/tray/tray_popup_utils.cc

@@ -217,13 +217,6 @@ views::ImageView* TrayPopupUtils::CreateMainImageView() {
   return image;
 }
 
-views::Slider* TrayPopupUtils::CreateSlider(views::SliderListener* listener) {
-  views::Slider* slider = new views::Slider(listener);
-  slider->SetBorder(views::CreateEmptyBorder(
-      gfx::Insets(0, kTrayPopupSliderHorizontalPadding)));
-  return slider;
-}
-
 views::ToggleButton* TrayPopupUtils::CreateToggleButton(
     views::ButtonListener* listener,
     int accessible_name_id) {

ash/system/tray/tray_popup_utils.h

@@ -25,8 +25,6 @@ class Label;
 class LabelButton;
 class Painter;
 class Separator;
-class Slider;
-class SliderListener;
 class ToggleButton;
 }  // namespace views
 
@@ -105,10 +103,6 @@ class TrayPopupUtils {
   // TODO(bruthig): Update all system menu rows to use this.
   static views::ImageView* CreateMainImageView();
 
-  // Returns a slider configured for proper layout within a TriView container
-  // with a FillLayout.
-  static views::Slider* CreateSlider(views::SliderListener* listener);
-
   // Returns a ToggleButton that has been configured for system menu layout.
   static views::ToggleButton* CreateToggleButton(
       views::ButtonListener* listener,

ash/system/unified/unified_slider_view.cc

@@ -28,11 +28,10 @@ using AshColorMode = AshColorProvider::AshColorMode;
 
 namespace {
 
-views::Slider* CreateSlider(UnifiedSliderListener* listener, bool readonly) {
-  if (readonly)
-    return new ReadOnlySlider();
-
-  return new SystemSlider(listener);
+std::unique_ptr<views::Slider> CreateSlider(UnifiedSliderListener* listener,
+                                            bool readonly) {
+  return readonly ? std::make_unique<ReadOnlySlider>()
+                  : std::make_unique<SystemSlider>(listener);
 }
 
 }  // namespace
@@ -53,7 +52,7 @@ SkColor SystemSlider::GetTroughColor() const {
   return AshColorProvider::Get()->GetDisabledColor(GetThumbColor());
 }
 
-ReadOnlySlider::ReadOnlySlider() : SystemSlider(nullptr) {}
+ReadOnlySlider::ReadOnlySlider() : SystemSlider() {}
 
 bool ReadOnlySlider::OnMousePressed(const ui::MouseEvent& event) {
   return false;
@@ -180,15 +179,15 @@ UnifiedSliderView::UnifiedSliderView(UnifiedSliderListener* listener,
                                      const gfx::VectorIcon& icon,
                                      int accessible_name_id,
                                      bool readonly)
-    : button_(new UnifiedSliderButton(listener, icon, accessible_name_id)),
-      slider_(CreateSlider(listener, readonly)) {
+    : button_(AddChildView(
+          std::make_unique<UnifiedSliderButton>(listener,
+                                                icon,
+                                                accessible_name_id))),
+      slider_(AddChildView(CreateSlider(listener, readonly))) {
   auto* layout = SetLayoutManager(std::make_unique<views::BoxLayout>(
       views::BoxLayout::Orientation::kHorizontal, kUnifiedSliderRowPadding,
       kUnifiedSliderViewSpacing));
 
-  AddChildView(button_);
-  AddChildView(slider_);
-
   // Prevent an accessibility event while initiallizing this view. Typically
   // the first update of the slider value is conducted by the caller function
   // to reflect the current value.

ash/system/unified/unified_slider_view.h

@@ -26,7 +26,7 @@ class UnifiedSliderListener : public views::ButtonListener,
 // Custom slider for the system menu to use different color scheme.
 class SystemSlider : public views::Slider {
  public:
-  explicit SystemSlider(views::SliderListener* listener);
+  explicit SystemSlider(views::SliderListener* listener = nullptr);
 
  private:
   SkColor GetThumbColor() const override;

ui/views/controls/slider.h

@@ -47,7 +47,7 @@ class VIEWS_EXPORT Slider : public View, public gfx::AnimationDelegate {
  public:
   METADATA_HEADER(Slider);
 
-  explicit Slider(SliderListener* listener);
+  explicit Slider(SliderListener* listener = nullptr);
   ~Slider() override;
 
   float GetValue() const;

ui/views/controls/slider_unittest.cc

@@ -25,6 +25,7 @@
 #include "ui/views/test/slider_test_api.h"
 #include "ui/views/test/views_test_base.h"
 #include "ui/views/view.h"
+#include "ui/views/widget/unique_widget_ptr.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/widget/widget_utils.h"
@@ -169,7 +170,7 @@ class SliderTest : public views::ViewsTestBase {
   // The maximum y value within the bounds of the slider.
   int max_y_ = 0;
   // The widget container for the slider being tested.
-  views::Widget* widget_ = nullptr;
+  views::UniqueWidgetPtr widget_;
   // An event generator.
   std::unique_ptr<ui::test::EventGenerator> event_generator_;
 
@@ -179,10 +180,9 @@ class SliderTest : public views::ViewsTestBase {
 void SliderTest::SetUp() {
   views::ViewsTestBase::SetUp();
 
-  slider_ = new Slider(nullptr);
-  View* view = slider_;
-  gfx::Size size = view->GetPreferredSize();
-  view->SetSize(size);
+  auto slider = std::make_unique<Slider>();
+  gfx::Size size = slider->GetPreferredSize();
+  slider->SetSize(size);
   max_x_ = size.width() - 1;
   max_y_ = size.height() - 1;
   default_locale_ = base::i18n::GetConfiguredLocale();
@@ -191,19 +191,17 @@ void SliderTest::SetUp() {
       CreateParams(views::Widget::InitParams::TYPE_WINDOW_FRAMELESS));
   init_params.bounds = gfx::Rect(size);
 
-  widget_ = new views::Widget();
+  widget_ = std::make_unique<Widget>();
   widget_->Init(std::move(init_params));
-  widget_->SetContentsView(slider_);
+  slider_ = widget_->SetContentsView(std::move(slider));
   widget_->Show();
 
   event_generator_ =
-      std::make_unique<ui::test::EventGenerator>(GetRootWindow(widget_));
+      std::make_unique<ui::test::EventGenerator>(GetRootWindow(widget_.get()));
 }
 
 void SliderTest::TearDown() {
-  if (widget_ && !widget_->IsClosed())
-    widget_->Close();
-
+  widget_.reset();
   base::i18n::SetICUDefaultLocale(default_locale_);
 
   views::ViewsTestBase::TearDown();