views: Make ImageButton and ToggleButton default constructible

This CL is part of the effort to make Views default
constructible, allowing UI to be built in a declarative fashion.

Bug: 1108460
Change-Id: I4f6d6a9e271990ead0e9e28fe7ebc3b2da401ad2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2330632
Commit-Queue: Keren Zhu <kerenzhu@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Auto-Submit: Keren Zhu <kerenzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793517}

chrome/browser/ui/views/frame/desktop_linux_browser_frame_view_layout_unittest.cc

@@ -151,10 +151,9 @@ class DesktopLinuxBrowserFrameViewLayoutTest : public ChromeViewsTestBase {
 
  protected:
   views::ImageButton* InitWindowCaptionButton(ViewID view_id) {
-    views::ImageButton* button = new views::ImageButton(nullptr);
+    auto button = std::make_unique<views::ImageButton>();
     button->SetID(view_id);
-    root_view_->AddChildView(button);
-    return button;
+    return root_view_->AddChildView(std::move(button));
   }
 
   void ResetNativeNavButtonImagesFromButtonProvider() {

chrome/browser/ui/views/frame/opaque_browser_frame_view_layout_unittest.cc

@@ -138,13 +138,15 @@ class OpaqueBrowserFrameViewLayoutTest
  protected:
   views::ImageButton* InitWindowCaptionButton(ViewID view_id,
                                               const gfx::Size& size) {
-    views::ImageButton* button = new views::ImageButton(nullptr);
+    auto button = std::make_unique<views::ImageButton>();
     gfx::ImageSkiaRep rep(size, 1.0f);
     gfx::ImageSkia image(rep);
     button->SetImage(views::Button::STATE_NORMAL, &image);
     button->SetID(view_id);
-    root_view_->AddChildView(button);
-    return button;
+
+    // OpaqueBrowserFrameViewLayout requires the id of a view is set before
+    // attaching it to a parent.
+    return root_view_->AddChildView(std::move(button));
   }
 
   void AddWindowTitleIcons() {

chrome/test/views/accessibility_checker_unittest.cc

@@ -27,8 +27,8 @@ TEST_F(AccessibilityCheckerTest, VerifyAccessibilityCheckerFailAndPass) {
   widget.Show();
 
   // Add the button.
-  views::ImageButton* button = new views::ImageButton(nullptr);
-  widget.GetContentsView()->AddChildView(button);
+  auto* button = widget.GetContentsView()->AddChildView(
+      std::make_unique<views::ImageButton>());
 
   // Accessibility test should pass as it is focusable but has a name.
   button->SetFocusBehavior(views::View::FocusBehavior::ALWAYS);

ui/views/controls/button/button_unittest.cc

@@ -474,7 +474,7 @@ TEST_F(ButtonTest, AsButton) {
   LabelButton label_button(nullptr, text);
   EXPECT_TRUE(Button::AsButton(&label_button));
 
-  ImageButton image_button(nullptr);
+  ImageButton image_button;
   EXPECT_TRUE(Button::AsButton(&image_button));
 
   Checkbox checkbox(text);
@@ -486,7 +486,7 @@ TEST_F(ButtonTest, AsButton) {
   MenuButton menu_button(text, nullptr);
   EXPECT_TRUE(Button::AsButton(&menu_button));
 
-  ToggleButton toggle_button(nullptr);
+  ToggleButton toggle_button;
   EXPECT_TRUE(Button::AsButton(&toggle_button));
 
   Label label;

ui/views/controls/button/image_button.h

@@ -29,7 +29,7 @@ class VIEWS_EXPORT ImageButton : public Button {
   // An enum describing the vertical alignment of images on Buttons.
   enum VerticalAlignment { ALIGN_TOP = 0, ALIGN_MIDDLE, ALIGN_BOTTOM };
 
-  explicit ImageButton(ButtonListener* listener);
+  explicit ImageButton(ButtonListener* listener = nullptr);
   ~ImageButton() override;
 
   // Returns the image for a given |state|.

ui/views/controls/button/image_button_unittest.cc

@@ -40,7 +40,7 @@ namespace views {
 using ImageButtonTest = ViewsTestBase;
 
 TEST_F(ImageButtonTest, Basics) {
-  ImageButton button(nullptr);
+  ImageButton button;
 
   // Our image to paint starts empty.
   EXPECT_TRUE(button.GetImageToPaint().isNull());
@@ -88,7 +88,7 @@ TEST_F(ImageButtonTest, Basics) {
 }
 
 TEST_F(ImageButtonTest, SetAndGetImage) {
-  ImageButton button(nullptr);
+  ImageButton button;
 
   // Images start as null.
   EXPECT_TRUE(button.GetImage(Button::STATE_NORMAL).isNull());
@@ -114,7 +114,7 @@ TEST_F(ImageButtonTest, SetAndGetImage) {
 }
 
 TEST_F(ImageButtonTest, ImagePositionWithBorder) {
-  ImageButton button(nullptr);
+  ImageButton button;
   gfx::ImageSkia image = CreateTestImage(20, 30);
   button.SetImage(Button::STATE_NORMAL, &image);
 
@@ -143,7 +143,7 @@ TEST_F(ImageButtonTest, ImagePositionWithBorder) {
 }
 
 TEST_F(ImageButtonTest, LeftAlignedMirrored) {
-  ImageButton button(nullptr);
+  ImageButton button;
   gfx::ImageSkia image = CreateTestImage(20, 30);
   button.SetImage(Button::STATE_NORMAL, &image);
   button.SetBounds(0, 0, 50, 30);
@@ -156,7 +156,7 @@ TEST_F(ImageButtonTest, LeftAlignedMirrored) {
 }
 
 TEST_F(ImageButtonTest, RightAlignedMirrored) {
-  ImageButton button(nullptr);
+  ImageButton button;
   gfx::ImageSkia image = CreateTestImage(20, 30);
   button.SetImage(Button::STATE_NORMAL, &image);
   button.SetBounds(0, 0, 50, 30);
@@ -171,7 +171,7 @@ TEST_F(ImageButtonTest, RightAlignedMirrored) {
 
 TEST_F(ImageButtonTest, PreferredSizeInvalidation) {
   Parent parent;
-  ImageButton button(nullptr);
+  ImageButton button;
   gfx::ImageSkia first_image = CreateTestImage(20, 30);
   gfx::ImageSkia second_image = CreateTestImage(50, 50);
   button.SetImage(Button::STATE_NORMAL, &first_image);

ui/views/controls/button/toggle_button.h

@@ -20,7 +20,7 @@ class VIEWS_EXPORT ToggleButton : public Button {
  public:
   METADATA_HEADER(ToggleButton);
 
-  explicit ToggleButton(ButtonListener* listener);
+  explicit ToggleButton(ButtonListener* listener = nullptr);
   ~ToggleButton() override;
 
   // AnimateIsOn() animates the state change to |is_on|; SetIsOn() doesn't.

ui/views/controls/button/toggle_button_unittest.cc

@@ -19,8 +19,7 @@ namespace views {
 
 class TestToggleButton : public ToggleButton {
  public:
-  explicit TestToggleButton(int* counter)
-      : ToggleButton(nullptr), counter_(counter) {}
+  explicit TestToggleButton(int* counter) : counter_(counter) {}
   ~TestToggleButton() override {
     // Calling SetInkDropMode() in this subclass allows this class's
     // implementation of RemoveInkDropLayer() to be called. The same