View ownership clarification in DialogPlate.

Bug: 648382
Change-Id: I1342c7735c5a78dbddd482de7f7a6c2ceb9b9e01
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2014126
Commit-Queue: Allen Bauer <kylixrd@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734130}

ash/assistant/ui/dialog_plate/dialog_plate.cc

@@ -264,13 +264,13 @@ void DialogPlate::InitLayout() {
       views::BoxLayout::CrossAxisAlignment::kCenter);
 
   // 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);
 
@@ -289,15 +289,15 @@ void DialogPlate::InitLayout() {
 }
 
 void DialogPlate::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 kHorizontalPaddingDip = 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, kHorizontalPaddingDip)));
@@ -309,41 +309,42 @@ void DialogPlate::InitKeyboardLayoutContainer() {
       assistant::ui::GetDefaultFontList().DeriveWithSizeDelta(2);
 
   // Textfield.
-  textfield_ = new views::Textfield();
-  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<views::Textfield>();
+  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_ = keyboard_layout_container_->AddChildView(
+  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));
 
-  input_modality_layout_container_->AddChildView(keyboard_layout_container_);
+  keyboard_layout_container_ = input_modality_layout_container_->AddChildView(
+      std::move(keyboard_layout_container));
 }
 
 void DialogPlate::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);
 
   constexpr int kLeftPaddingDip = 8;
-  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,
           gfx::Insets(0, kLeftPaddingDip, 0, 0)));
@@ -352,32 +353,29 @@ void DialogPlate::InitVoiceLayoutContainer() {
       views::BoxLayout::CrossAxisAlignment::kCenter);
 
   // Keyboard input toggle.
-  keyboard_input_toggle_ = voice_layout_container_->AddChildView(
+  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));
 
   // Spacer.
-  views::View* 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);
 
   // Animated voice input toggle.
   animated_voice_input_toggle_ =
-      new MicView(this, delegate_, AssistantButtonId::kVoiceInputToggle);
+      voice_layout_container->AddChildView(std::make_unique<MicView>(
+          this, delegate_, AssistantButtonId::kVoiceInputToggle));
   animated_voice_input_toggle_->SetAccessibleName(
       l10n_util::GetStringUTF16(IDS_ASH_ASSISTANT_DIALOG_PLATE_MIC_ACCNAME));
-  voice_layout_container_->AddChildView(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);
 
-  input_modality_layout_container_->AddChildView(voice_layout_container_);
+  voice_layout_container_ = input_modality_layout_container_->AddChildView(
+      std::move(voice_layout_container));
 }
 
 void DialogPlate::OnAnimationStarted(