Clarify view ownership in the assistant dialog.

Bug: 648382
Change-Id: I89d44f2b4ed34827d0451db4cbfa801a6c6cf3fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2013512Reviewed-by: Tao Wu <wutao@chromium.org>
Commit-Queue: Allen Bauer <kylixrd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734122}

ash/app_list/views/assistant/assistant_dialog_plate.cc

@@ -296,13 +296,13 @@ void AssistantDialogPlate::InitLayout() {
                            /*animate=*/false);
 
   // Input modality layout container.
-  input_modality_layout_container_ = new views::View();
+  input_modality_layout_container_ =
+      AddChildView(std::make_unique<views::View>());
   input_modality_layout_container_->SetLayoutManager(
       std::make_unique<views::FillLayout>());
   input_modality_layout_container_->SetPaintToLayer();
   input_modality_layout_container_->layer()->SetFillsBoundsOpaquely(false);
   input_modality_layout_container_->layer()->SetMasksToBounds(true);
-  AddChildView(input_modality_layout_container_);
 
   layout_manager->SetFlexForView(input_modality_layout_container_, 1);
 
@@ -314,14 +314,14 @@ void AssistantDialogPlate::InitLayout() {
 }
 
 void AssistantDialogPlate::InitKeyboardLayoutContainer() {
-  keyboard_layout_container_ = new views::View();
-  keyboard_layout_container_->SetPaintToLayer();
-  keyboard_layout_container_->layer()->SetFillsBoundsOpaquely(false);
-  keyboard_layout_container_->layer()->SetOpacity(0.f);
+  auto keyboard_layout_container = std::make_unique<views::View>();
+  keyboard_layout_container->SetPaintToLayer();
+  keyboard_layout_container->layer()->SetFillsBoundsOpaquely(false);
+  keyboard_layout_container->layer()->SetOpacity(0.f);
 
   constexpr int kLeftPaddingDip = 16;
   views::BoxLayout* layout_manager =
-      keyboard_layout_container_->SetLayoutManager(
+      keyboard_layout_container->SetLayoutManager(
           std::make_unique<views::BoxLayout>(
               views::BoxLayout::Orientation::kHorizontal,
               gfx::Insets(0, kLeftPaddingDip, 0, 0)));
@@ -333,42 +333,44 @@ void AssistantDialogPlate::InitKeyboardLayoutContainer() {
       assistant::ui::GetDefaultFontList().DeriveWithSizeDelta(2);
 
   // Textfield.
-  textfield_ = new AssistantTextfield();
-  textfield_->SetBackgroundColor(SK_ColorTRANSPARENT);
-  textfield_->SetBorder(views::NullBorder());
-  textfield_->set_controller(this);
-  textfield_->SetFontList(font_list);
-  textfield_->set_placeholder_font_list(font_list);
+  auto textfield = std::make_unique<AssistantTextfield>();
+  textfield->SetBackgroundColor(SK_ColorTRANSPARENT);
+  textfield->SetBorder(views::NullBorder());
+  textfield->set_controller(this);
+  textfield->SetFontList(font_list);
+  textfield->set_placeholder_font_list(font_list);
 
   auto textfield_hint =
       l10n_util::GetStringUTF16(IDS_ASH_ASSISTANT_DIALOG_PLATE_HINT);
-  textfield_->SetPlaceholderText(textfield_hint);
-  textfield_->SetAccessibleName(textfield_hint);
-  textfield_->set_placeholder_text_color(kTextColorSecondary);
-  textfield_->SetTextColor(kTextColorPrimary);
-  keyboard_layout_container_->AddChildView(textfield_);
+  textfield->SetPlaceholderText(textfield_hint);
+  textfield->SetAccessibleName(textfield_hint);
+  textfield->set_placeholder_text_color(kTextColorSecondary);
+  textfield->SetTextColor(kTextColorPrimary);
+  textfield_ = keyboard_layout_container->AddChildView(std::move(textfield));
 
   layout_manager->SetFlexForView(textfield_, 1);
 
   // Voice input toggle.
-  voice_input_toggle_ =
+  std::unique_ptr<AssistantButton> voice_input_toggle =
       AssistantButton::Create(this, kMicIcon, kButtonSizeDip, kIconSizeDip,
                               IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_ACCNAME,
                               AssistantButtonId::kVoiceInputToggle,
                               IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_TOOLTIP);
-  voice_input_toggle_->SetID(AssistantViewID::kVoiceInputToggle);
-  keyboard_layout_container_->AddChildView(voice_input_toggle_);
+  voice_input_toggle->SetID(AssistantViewID::kVoiceInputToggle);
+  voice_input_toggle_ =
+      keyboard_layout_container->AddChildView(std::move(voice_input_toggle));
 
-  input_modality_layout_container_->AddChildView(keyboard_layout_container_);
+  keyboard_layout_container_ = input_modality_layout_container_->AddChildView(
+      std::move(keyboard_layout_container));
 }
 
 void AssistantDialogPlate::InitVoiceLayoutContainer() {
-  voice_layout_container_ = new views::View();
-  voice_layout_container_->SetPaintToLayer();
-  voice_layout_container_->layer()->SetFillsBoundsOpaquely(false);
-  voice_layout_container_->layer()->SetOpacity(0.f);
+  auto voice_layout_container = std::make_unique<views::View>();
+  voice_layout_container->SetPaintToLayer();
+  voice_layout_container->layer()->SetFillsBoundsOpaquely(false);
+  voice_layout_container->layer()->SetOpacity(0.f);
 
-  views::BoxLayout* layout_manager = voice_layout_container_->SetLayoutManager(
+  views::BoxLayout* layout_manager = voice_layout_container->SetLayoutManager(
       std::make_unique<views::BoxLayout>(
           views::BoxLayout::Orientation::kHorizontal));
 
@@ -382,38 +384,38 @@ void AssistantDialogPlate::InitVoiceLayoutContainer() {
   constexpr int difference =
       /*keyboard_input_toggle_width=*/kButtonSizeDip -
       /*molecule_icon_width=*/kIconSizeDip;
-  views::View* offset = new views::View();
+  auto offset = std::make_unique<views::View>();
   offset->SetPreferredSize(gfx::Size(difference, 1));
-  voice_layout_container_->AddChildView(offset);
+  voice_layout_container->AddChildView(std::move(offset));
 
   // Spacer.
-  views::View* spacer = new views::View();
-  voice_layout_container_->AddChildView(spacer);
-  layout_manager->SetFlexForView(spacer, 1);
+  auto spacer = std::make_unique<views::View>();
+  layout_manager->SetFlexForView(
+      voice_layout_container->AddChildView(std::move(spacer)), 1);
 
   // Animated voice input toggle.
-  animated_voice_input_toggle_ =
-      new MicView(this, delegate_, AssistantButtonId::kVoiceInputToggle);
-  animated_voice_input_toggle_->SetID(AssistantViewID::kMicView);
-  animated_voice_input_toggle_->SetAccessibleName(
+  auto animated_voice_input_toggle = std::make_unique<MicView>(
+      this, delegate_, AssistantButtonId::kVoiceInputToggle);
+  animated_voice_input_toggle->SetID(AssistantViewID::kMicView);
+  animated_voice_input_toggle->SetAccessibleName(
       l10n_util::GetStringUTF16(IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_ACCNAME));
-  voice_layout_container_->AddChildView(animated_voice_input_toggle_);
+  animated_voice_input_toggle_ = voice_layout_container->AddChildView(
+      std::move(animated_voice_input_toggle));
 
   // Spacer.
-  spacer = new views::View();
-  voice_layout_container_->AddChildView(spacer);
-  layout_manager->SetFlexForView(spacer, 1);
+  layout_manager->SetFlexForView(
+      voice_layout_container->AddChildView(std::make_unique<views::View>()), 1);
 
   // Keyboard input toggle.
-  keyboard_input_toggle_ =
+  keyboard_input_toggle_ = voice_layout_container->AddChildView(
       AssistantButton::Create(this, kKeyboardIcon, kButtonSizeDip, kIconSizeDip,
                               IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_ACCNAME,
                               AssistantButtonId::kKeyboardInputToggle,
-                              IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_TOOLTIP);
+                              IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_TOOLTIP));
   keyboard_input_toggle_->SetID(AssistantViewID::kKeyboardInputToggle);
-  voice_layout_container_->AddChildView(keyboard_input_toggle_);
 
-  input_modality_layout_container_->AddChildView(voice_layout_container_);
+  voice_layout_container_ = input_modality_layout_container_->AddChildView(
+      std::move(voice_layout_container));
 }
 
 void AssistantDialogPlate::UpdateModalityVisibility() {

ash/app_list/views/assistant/assistant_dialog_plate.h

@@ -90,14 +90,15 @@ class APP_LIST_EXPORT AssistantDialogPlate
 
   AssistantViewDelegate* const delegate_;
 
-  LogoView* molecule_icon_;                       // Owned by view hierarchy.
-  views::View* input_modality_layout_container_;  // Owned by view hierarchy.
-  views::View* keyboard_layout_container_;        // Owned by view hierarchy.
-  views::View* voice_layout_container_;           // Owned by view hierarchy.
-  views::ImageButton* keyboard_input_toggle_;     // Owned by view hierarchy.
-  views::ImageButton* voice_input_toggle_;        // Owned by view hierarchy.
-  MicView* animated_voice_input_toggle_;          // Owned by view hierarchy.
-  views::Textfield* textfield_;                   // Owned by view hierarchy.
+  // The following views are all owned by the view hierarchy
+  LogoView* molecule_icon_ = nullptr;
+  views::View* input_modality_layout_container_ = nullptr;
+  views::View* keyboard_layout_container_ = nullptr;
+  views::View* voice_layout_container_ = nullptr;
+  views::ImageButton* keyboard_input_toggle_ = nullptr;
+  views::ImageButton* voice_input_toggle_ = nullptr;
+  MicView* animated_voice_input_toggle_ = nullptr;
+  views::Textfield* textfield_ = nullptr;
 
   std::unique_ptr<ui::CallbackLayerAnimationObserver> animation_observer_;
   std::unique_ptr<AssistantQueryHistory::Iterator> query_history_iterator_;

ash/assistant/ui/base/assistant_button.cc

@@ -51,15 +51,16 @@ AssistantButton::AssistantButton(AssistantButtonListener* listener,
 AssistantButton::~AssistantButton() = default;
 
 // static
-AssistantButton* AssistantButton::Create(AssistantButtonListener* listener,
-                                         const gfx::VectorIcon& icon,
-                                         int size_in_dip,
-                                         int icon_size_in_dip,
-                                         int accessible_name_id,
-                                         AssistantButtonId button_id,
-                                         base::Optional<int> tooltip_id,
-                                         SkColor icon_color) {
-  auto* button = new AssistantButton(listener, button_id);
+std::unique_ptr<AssistantButton> AssistantButton::Create(
+    AssistantButtonListener* listener,
+    const gfx::VectorIcon& icon,
+    int size_in_dip,
+    int icon_size_in_dip,
+    int accessible_name_id,
+    AssistantButtonId button_id,
+    base::Optional<int> tooltip_id,
+    SkColor icon_color) {
+  auto button = std::make_unique<AssistantButton>(listener, button_id);
   button->SetAccessibleName(l10n_util::GetStringUTF16(accessible_name_id));
 
   if (tooltip_id)

ash/assistant/ui/base/assistant_button.h

@@ -36,14 +36,15 @@ class COMPONENT_EXPORT(ASSISTANT_UI) AssistantButton
   ~AssistantButton() override;
 
   // Creates a button with the default Assistant styles.
-  static AssistantButton* Create(AssistantButtonListener* listener,
-                                 const gfx::VectorIcon& icon,
-                                 int size_in_dip,
-                                 int icon_size_in_dip,
-                                 int accessible_name_id,
-                                 AssistantButtonId button_id,
-                                 base::Optional<int> tooltip_id = base::nullopt,
-                                 SkColor icon_color = gfx::kGoogleGrey700);
+  static std::unique_ptr<AssistantButton> Create(
+      AssistantButtonListener* listener,
+      const gfx::VectorIcon& icon,
+      int size_in_dip,
+      int icon_size_in_dip,
+      int accessible_name_id,
+      AssistantButtonId button_id,
+      base::Optional<int> tooltip_id = base::nullopt,
+      SkColor icon_color = gfx::kGoogleGrey700);
 
   AssistantButtonId GetAssistantButtonId() const { return id_; }
 

ash/assistant/ui/caption_bar.cc

@@ -29,10 +29,11 @@ constexpr int kVectorIconSizeDip = 12;
 
 // CaptionButton ---------------------------------------------------------------
 
-AssistantButton* CreateCaptionButton(const gfx::VectorIcon& icon,
-                                     int accessible_name_id,
-                                     AssistantButtonId button_id,
-                                     AssistantButtonListener* listener) {
+std::unique_ptr<AssistantButton> CreateCaptionButton(
+    const gfx::VectorIcon& icon,
+    int accessible_name_id,
+    AssistantButtonId button_id,
+    AssistantButtonListener* listener) {
   return AssistantButton::Create(listener, icon, kCaptionButtonSizeDip,
                                  kVectorIconSizeDip, accessible_name_id,
                                  button_id);
@@ -123,10 +124,8 @@ void CaptionBar::InitLayout() {
                                 AssistantButtonId::kBack, this));
 
   // Spacer.
-  views::View* spacer = new views::View();
-  AddChildView(spacer);
-
-  layout_manager->SetFlexForView(spacer, 1);
+  auto spacer = std::make_unique<views::View>();
+  layout_manager->SetFlexForView(AddChildView(std::move(spacer)), 1);
 
   // Minimize.
   AddButton(CreateCaptionButton(views::kWindowControlMinimizeIcon,
@@ -139,9 +138,9 @@ void CaptionBar::InitLayout() {
                                 AssistantButtonId::kClose, this));
 }
 
-void CaptionBar::AddButton(AssistantButton* button) {
-  buttons_.push_back(button);
-  AddChildView(button);
+void CaptionBar::AddButton(std::unique_ptr<AssistantButton> button) {
+  buttons_.push_back(button.get());
+  AddChildView(std::move(button));
 }
 
 void CaptionBar::HandleButton(AssistantButtonId id) {

ash/assistant/ui/caption_bar.h

@@ -69,7 +69,7 @@ class COMPONENT_EXPORT(ASSISTANT_UI) CaptionBar : public views::View,
 
  private:
   void InitLayout();
-  void AddButton(AssistantButton* button);
+  void AddButton(std::unique_ptr<AssistantButton> button);
   void HandleButton(AssistantButtonId id);
   AssistantButton* GetButtonWithId(AssistantButtonId id);
 

ash/assistant/ui/dialog_plate/dialog_plate.cc

@@ -278,12 +278,11 @@ void DialogPlate::InitLayout() {
   InitVoiceLayoutContainer();
 
   // Settings.
-  settings_button_ = AssistantButton::Create(
+  settings_button_ = AddChildView(AssistantButton::Create(
       this, kSettingsIcon, kButtonSizeDip, kIconSizeDip,
       IDS_ASH_ASSISTANT_DIALOG_PLATE_SETTINGS_ACCNAME_TOOLTIP,
       AssistantButtonId::kSettings,
-      IDS_ASH_ASSISTANT_DIALOG_PLATE_SETTINGS_ACCNAME_TOOLTIP);
-  AddChildView(settings_button_);
+      IDS_ASH_ASSISTANT_DIALOG_PLATE_SETTINGS_ACCNAME_TOOLTIP));
 
   // Artificially trigger event to set initial state.
   OnInputModalityChanged(delegate_->GetInteractionModel()->input_modality());
@@ -328,12 +327,11 @@ void DialogPlate::InitKeyboardLayoutContainer() {
   layout_manager->SetFlexForView(textfield_, 1);
 
   // Voice input toggle.
-  voice_input_toggle_ =
+  voice_input_toggle_ = keyboard_layout_container_->AddChildView(
       AssistantButton::Create(this, kMicIcon, kButtonSizeDip, kIconSizeDip,
                               IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_ACCNAME,
                               AssistantButtonId::kVoiceInputToggle,
-                              IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_TOOLTIP);
-  keyboard_layout_container_->AddChildView(voice_input_toggle_);
+                              IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_TOOLTIP));
 
   input_modality_layout_container_->AddChildView(keyboard_layout_container_);
 }
@@ -354,12 +352,11 @@ void DialogPlate::InitVoiceLayoutContainer() {
       views::BoxLayout::CrossAxisAlignment::kCenter);
 
   // Keyboard input toggle.
-  keyboard_input_toggle_ =
+  keyboard_input_toggle_ = voice_layout_container_->AddChildView(
       AssistantButton::Create(this, kKeyboardIcon, kButtonSizeDip, kIconSizeDip,
                               IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_ACCNAME,
                               AssistantButtonId::kKeyboardInputToggle,
-                              IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_TOOLTIP);
-  voice_layout_container_->AddChildView(keyboard_input_toggle_);
+                              IDS_ASH_ASSISTANT_DIALOG_PLATE_KEYBOARD_TOOLTIP));
 
   // Spacer.
   views::View* spacer = new views::View();

ash/assistant/ui/main_stage/assistant_footer_view.cc

@@ -76,7 +76,8 @@ void AssistantFooterView::InitLayout() {
       chromeos::assistant::prefs::ConsentStatus::kActivityControlAccepted;
 
   // Suggestion container.
-  suggestion_container_ = new SuggestionContainerView(delegate_);
+  suggestion_container_ =
+      AddChildView(std::make_unique<SuggestionContainerView>(delegate_));
   suggestion_container_->set_can_process_events_within_subtree(consent_given);
 
   // Suggestion container will be animated on its own layer.
@@ -85,10 +86,9 @@ void AssistantFooterView::InitLayout() {
   suggestion_container_->layer()->SetOpacity(consent_given ? 1.f : 0.f);
   suggestion_container_->SetVisible(consent_given);
 
-  AddChildView(suggestion_container_);
 
   // Opt in view.
-  opt_in_view_ = new AssistantOptInView(delegate_);
+  opt_in_view_ = AddChildView(std::make_unique<AssistantOptInView>(delegate_));
   opt_in_view_->set_can_process_events_within_subtree(!consent_given);
 
   // Opt in view will be animated on its own layer.
@@ -96,8 +96,6 @@ void AssistantFooterView::InitLayout() {
   opt_in_view_->layer()->SetFillsBoundsOpaquely(false);
   opt_in_view_->layer()->SetOpacity(consent_given ? 0.f : 1.f);
   opt_in_view_->SetVisible(!consent_given);
-
-  AddChildView(opt_in_view_);
 }
 
 void AssistantFooterView::OnAssistantConsentStatusChanged(int consent_status) {

ash/assistant/ui/main_stage/assistant_main_stage.cc

@@ -193,21 +193,20 @@ void AssistantMainStage::InitContentLayoutContainer() {
   // preferred size and visibility change events in AssistantMainStage. This is
   // necessary because |content_layout_container_| may not change size in
   // response to these events, necessitating an explicit layout pass.
-  content_layout_container_ = new views::View();
+  auto content_layout_container = std::make_unique<views::View>();
 
-  views::BoxLayout* layout_manager =
-      content_layout_container_->SetLayoutManager(
-          std::make_unique<views::BoxLayout>(
-              views::BoxLayout::Orientation::kVertical));
+  views::BoxLayout* layout_manager = content_layout_container->SetLayoutManager(
+      std::make_unique<views::BoxLayout>(
+          views::BoxLayout::Orientation::kVertical));
 
   // Header.
-  header_ = new AssistantHeaderView(delegate_);
-  content_layout_container_->AddChildView(header_);
+  header_ = content_layout_container->AddChildView(
+      std::make_unique<AssistantHeaderView>(delegate_));
 
   // UI element container.
-  ui_element_container_ = new UiElementContainerView(delegate_);
+  ui_element_container_ = content_layout_container->AddChildView(
+      std::make_unique<UiElementContainerView>(delegate_));
   ui_element_container_->AddObserver(this);
-  content_layout_container_->AddChildView(ui_element_container_);
 
   layout_manager->SetFlexForView(ui_element_container_, 1,
                                  /*use_min_size=*/true);
@@ -217,20 +216,20 @@ void AssistantMainStage::InitContentLayoutContainer() {
   // its visibility changes, its parent container will still reserve the same
   // layout space. This prevents jank that would otherwise occur due to
   // |ui_element_container_| claiming that empty space.
-  views::View* footer_container = new views::View();
+  auto footer_container = std::make_unique<views::View>();
   footer_container->SetLayoutManager(std::make_unique<views::FillLayout>());
 
-  footer_ = new AssistantFooterView(delegate_);
+  footer_ = footer_container->AddChildView(
+      std::make_unique<AssistantFooterView>(delegate_));
   footer_->AddObserver(this);
 
   // The footer will be animated on its own layer.
   footer_->SetPaintToLayer();
   footer_->layer()->SetFillsBoundsOpaquely(false);
 
-  footer_container->AddChildView(footer_);
-  content_layout_container_->AddChildView(footer_container);
+  content_layout_container->AddChildView(std::move(footer_container));
 
-  AddChildView(content_layout_container_);
+  content_layout_container_ = AddChildView(std::move(content_layout_container));
 }
 
 void AssistantMainStage::InitQueryLayoutContainer() {
@@ -238,12 +237,10 @@ void AssistantMainStage::InitQueryLayoutContainer() {
   // preferred size and visibility change events in AssistantMainStage. This is
   // necessary because |query_layout_container_| may not change size in response
   // to these events, thereby requiring an explicit layout pass.
-  query_layout_container_ = new views::View();
+  query_layout_container_ = AddChildView(std::make_unique<views::View>());
   query_layout_container_->AddObserver(this);
   query_layout_container_->set_can_process_events_within_subtree(false);
   query_layout_container_->SetLayoutManager(std::make_unique<StackLayout>());
-
-  AddChildView(query_layout_container_);
 }
 
 void AssistantMainStage::InitOverlayLayoutContainer() {
@@ -251,32 +248,32 @@ void AssistantMainStage::InitOverlayLayoutContainer() {
   // the content and query layout containers. As such, its children appear over
   // top of and do not cause repositioning to any of content/query layout's
   // underlying views. Events pass through the overlay layout container.
-  overlay_layout_container_ = new views::View();
-  overlay_layout_container_->set_can_process_events_within_subtree(false);
+  auto overlay_layout_container = std::make_unique<views::View>();
+  overlay_layout_container->set_can_process_events_within_subtree(false);
 
-  auto* stack_layout = overlay_layout_container_->SetLayoutManager(
+  auto* stack_layout = overlay_layout_container->SetLayoutManager(
       std::make_unique<StackLayout>());
 
   // Greeting label.
-  greeting_label_ = new views::Label(
+  auto greeting_label = std::make_unique<views::Label>(
       l10n_util::GetStringUTF16(IDS_ASH_ASSISTANT_PROMPT_DEFAULT));
-  greeting_label_->SetAutoColorReadabilityEnabled(false);
-  greeting_label_->SetBorder(
+  greeting_label->SetAutoColorReadabilityEnabled(false);
+  greeting_label->SetBorder(
       views::CreateEmptyBorder(kGreetingLabelMarginTopDip, 0, 0, 0));
-  greeting_label_->SetEnabledColor(kTextColorPrimary);
-  greeting_label_->SetFontList(
-      assistant::ui::GetDefaultFontList()
-          .DeriveWithSizeDelta(8)
-          .DeriveWithWeight(gfx::Font::Weight::MEDIUM));
-  greeting_label_->SetHorizontalAlignment(
+  greeting_label->SetEnabledColor(kTextColorPrimary);
+  greeting_label->SetFontList(assistant::ui::GetDefaultFontList()
+                                  .DeriveWithSizeDelta(8)
+                                  .DeriveWithWeight(gfx::Font::Weight::MEDIUM));
+  greeting_label->SetHorizontalAlignment(
       gfx::HorizontalAlignment::ALIGN_CENTER);
-  greeting_label_->SetMultiLine(true);
+  greeting_label->SetMultiLine(true);
 
   // The greeting label will be animated on its own layer.
-  greeting_label_->SetPaintToLayer();
-  greeting_label_->SetBackground(views::CreateSolidBackground(SK_ColorWHITE));
+  greeting_label->SetPaintToLayer();
+  greeting_label->SetBackground(views::CreateSolidBackground(SK_ColorWHITE));
 
-  overlay_layout_container_->AddChildView(greeting_label_);
+  greeting_label_ =
+      overlay_layout_container->AddChildView(std::move(greeting_label));
 
   // We need to stretch |greeting_label_| to match its parent so that it
   // won't use heuristics in Label to infer line breaking, which seems to cause
@@ -285,18 +282,19 @@ void AssistantMainStage::InitOverlayLayoutContainer() {
       greeting_label_, StackLayout::RespectDimension::kHeight);
 
   // Progress indicator.
-  progress_indicator_ = new AssistantProgressIndicator();
-  progress_indicator_->SetBorder(
+  auto progress_indicator = std::make_unique<AssistantProgressIndicator>();
+  progress_indicator->SetBorder(
       views::CreateEmptyBorder(kProgressIndicatorMarginTopDip, 0, 0, 0));
 
   // The progress indicator will be animated on its own layer.
-  progress_indicator_->SetPaintToLayer();
-  progress_indicator_->layer()->SetFillsBoundsOpaquely(false);
-  progress_indicator_->layer()->SetOpacity(0.f);
+  progress_indicator->SetPaintToLayer();
+  progress_indicator->layer()->SetFillsBoundsOpaquely(false);
+  progress_indicator->layer()->SetOpacity(0.f);
 
-  overlay_layout_container_->AddChildView(progress_indicator_);
+  progress_indicator_ =
+      overlay_layout_container->AddChildView(std::move(progress_indicator));
 
-  AddChildView(overlay_layout_container_);
+  overlay_layout_container_ = AddChildView(std::move(overlay_layout_container));
 }
 
 void AssistantMainStage::OnCommittedQueryChanged(const AssistantQuery& query) {
@@ -458,15 +456,14 @@ void AssistantMainStage::OnPendingQueryChanged(const AssistantQuery& query) {
   }
 
   if (!pending_query_view_) {
-    pending_query_view_ = new AssistantQueryView();
+    pending_query_view_ = query_layout_container_->AddChildView(
+        std::make_unique<AssistantQueryView>());
     pending_query_view_->AddObserver(this);
 
     // The query view will be animated on its own layer.
     pending_query_view_->SetPaintToLayer();
     pending_query_view_->layer()->SetFillsBoundsOpaquely(false);
 
-    query_layout_container_->AddChildView(pending_query_view_);
-
     // Starting from 0% opacity...
     pending_query_view_->layer()->SetOpacity(0.f);
 

ash/assistant/ui/main_stage/assistant_main_stage.h

@@ -93,13 +93,13 @@ class COMPONENT_EXPORT(ASSISTANT_UI) AssistantMainStage
   AssistantViewDelegate* const delegate_;  // Owned by Shell.
 
   // Content layout container and children. Owned by view hierarchy.
-  AssistantHeaderView* header_;
-  views::View* content_layout_container_;
-  UiElementContainerView* ui_element_container_;
-  AssistantFooterView* footer_;
+  AssistantHeaderView* header_ = nullptr;
+  views::View* content_layout_container_ = nullptr;
+  UiElementContainerView* ui_element_container_ = nullptr;
+  AssistantFooterView* footer_ = nullptr;
 
   // Query layout container and children. Owned by view hierarchy.
-  views::View* query_layout_container_;
+  views::View* query_layout_container_ = nullptr;
   AssistantQueryView* active_query_view_ = nullptr;
   AssistantQueryView* committed_query_view_ = nullptr;
   AssistantQueryView* pending_query_view_ = nullptr;

ash/assistant/ui/main_stage/assistant_opt_in_view.cc

@@ -134,7 +134,8 @@ void AssistantOptInView::InitLayout() {
       views::BoxLayout::MainAxisAlignment::kCenter);
 
   // Container.
-  container_ = new AssistantOptInContainer(/*listener=*/this);
+  container_ = AddChildView(
+      std::make_unique<AssistantOptInContainer>(/*listener=*/this));
 
   layout_manager =
       container_->SetLayoutManager(std::make_unique<views::BoxLayout>(
@@ -144,14 +145,12 @@ void AssistantOptInView::InitLayout() {
   layout_manager->set_cross_axis_alignment(
       views::BoxLayout::CrossAxisAlignment::kCenter);
 
-  AddChildView(container_);
-
   // Label.
-  label_ = new views::StyledLabel(base::string16(), /*listener=*/nullptr);
+  label_ = container_->AddChildView(std::make_unique<views::StyledLabel>(
+      base::string16(), /*listener=*/nullptr));
   label_->SetAutoColorReadabilityEnabled(false);
   label_->SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_CENTER);
 
-  container_->AddChildView(label_);
   container_->SetFocusForPlatform();
 
   UpdateLabel(AssistantState::Get()->consent_status().value_or(

ash/assistant/ui/main_stage/assistant_query_view.cc

@@ -80,12 +80,12 @@ void AssistantQueryView::InitLayout() {
       views::BoxLayout::CrossAxisAlignment::kStretch);
 
   // Label.
-  label_ = new views::StyledLabel(base::string16(), /*listener=*/nullptr);
+  label_ = AddChildView(std::make_unique<views::StyledLabel>(
+      base::string16(), /*listener=*/nullptr));
   label_->SetAutoColorReadabilityEnabled(false);
   label_->SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_CENTER);
   label_->SetLineHeight(kLineHeightDip);
   label_->SetBackground(views::CreateSolidBackground(SK_ColorWHITE));
-  AddChildView(label_);
 }
 
 void AssistantQueryView::SetQuery(const AssistantQuery& query) {

ash/assistant/ui/main_stage/suggestion_chip_view.cc

@@ -44,9 +44,7 @@ SuggestionChipView::Params::~Params() = default;
 
 SuggestionChipView::SuggestionChipView(const Params& params,
                                        views::ButtonListener* listener)
-    : Button(listener),
-      icon_view_(new views::ImageView()),
-      text_view_(new views::Label()) {
+    : Button(listener) {
   // Configure focus. Note that we don't install the default focus ring as we
   // use custom highlighting instead.
   SetFocusBehavior(FocusBehavior::ALWAYS);
@@ -89,6 +87,7 @@ void SuggestionChipView::InitLayout(const Params& params) {
       views::BoxLayout::CrossAxisAlignment::kCenter);
 
   // Icon.
+  icon_view_ = AddChildView(std::make_unique<views::ImageView>());
   const int icon_size =
       AppListConfig::instance().suggestion_chip_icon_dimension();
   icon_view_->SetImageSize(gfx::Size(icon_size, icon_size));
@@ -99,16 +98,14 @@ void SuggestionChipView::InitLayout(const Params& params) {
   else
     icon_view_->SetVisible(false);
 
-  AddChildView(icon_view_);
-
   // Text.
+  text_view_ = AddChildView(std::make_unique<views::Label>());
   text_view_->SetAutoColorReadabilityEnabled(false);
   text_view_->SetEnabledColor(kTextColor);
   text_view_->SetSubpixelRenderingEnabled(false);
   text_view_->SetFontList(
       assistant::ui::GetDefaultFontList().DeriveWithSizeDelta(1));
   SetText(params.text);
-  AddChildView(text_view_);
 }
 
 void SuggestionChipView::OnPaintBackground(gfx::Canvas* canvas) {