Add assistant button in launcher search box

Bug: b:112281423
Test: locally build and run
Change-Id: I6fc9fe7c462be053a54b48c8a6ffdc23e565bb83
Reviewed-on: https://chromium-review.googlesource.com/1173533
Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583493}

ash/app_list/BUILD.gn

@@ -101,6 +101,7 @@ component("app_list") {
     "//ash/app_menu",
     "//ash/assistant/ui:constants",
     "//ash/public/cpp/app_list/vector_icons",
+    "//ash/public/cpp/vector_icons",
     "//base",
     "//base:i18n",
     "//base/third_party/dynamic_annotations",

ash/app_list/app_list_controller_impl.cc

@@ -13,11 +13,14 @@
 #include "ash/app_list/views/app_list_main_view.h"
 #include "ash/app_list/views/app_list_view.h"
 #include "ash/app_list/views/contents_view.h"
+#include "ash/assistant/assistant_controller.h"
+#include "ash/assistant/assistant_ui_controller.h"
 #include "ash/public/cpp/app_list/answer_card_contents_registry.h"
 #include "ash/public/cpp/app_list/app_list_features.h"
 #include "ash/public/cpp/config.h"
 #include "ash/session/session_controller.h"
 #include "ash/shell.h"
+#include "ash/voice_interaction/voice_interaction_controller.h"
 #include "ash/wallpaper/wallpaper_controller.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
 #include "base/logging.h"
@@ -40,7 +43,8 @@ namespace ash {
 
 AppListControllerImpl::AppListControllerImpl()
     : presenter_(std::make_unique<AppListPresenterDelegateImpl>(this)),
-      is_home_launcher_enabled_(app_list::features::IsHomeLauncherEnabled()) {
+      is_home_launcher_enabled_(app_list::features::IsHomeLauncherEnabled()),
+      voice_interaction_binding_(this) {
   model_.AddObserver(this);
 
   // Create only for non-mash. Mash uses window tree embed API to get a
@@ -62,6 +66,10 @@ AppListControllerImpl::AppListControllerImpl()
   Shell::Get()->wallpaper_controller()->AddObserver(this);
   Shell::Get()->AddShellObserver(this);
   keyboard::KeyboardController::Get()->AddObserver(this);
+
+  mojom::VoiceInteractionObserverPtr ptr;
+  voice_interaction_binding_.Bind(mojo::MakeRequest(&ptr));
+  Shell::Get()->voice_interaction_controller()->AddObserver(std::move(ptr));
 }
 
 AppListControllerImpl::~AppListControllerImpl() {
@@ -524,6 +532,15 @@ void AppListControllerImpl::OnWallpaperPreviewEnded() {
   UpdateHomeLauncherVisibility();
 }
 
+void AppListControllerImpl::OnVoiceInteractionSettingsEnabled(bool enabled) {
+  UpdateAssistantVisibility();
+}
+
+void AppListControllerImpl::OnAssistantFeatureAllowedChanged(
+    mojom::AssistantAllowedState state) {
+  UpdateAssistantVisibility();
+}
+
 bool AppListControllerImpl::IsHomeLauncherEnabledInTabletMode() const {
   return is_home_launcher_enabled_ && Shell::Get()
                                           ->tablet_mode_controller()
@@ -533,6 +550,14 @@ bool AppListControllerImpl::IsHomeLauncherEnabledInTabletMode() const {
 ////////////////////////////////////////////////////////////////////////////////
 // Methods of |client_|:
 
+void AppListControllerImpl::StartAssistant() {
+  if (!IsHomeLauncherEnabledInTabletMode())
+    DismissAppList();
+
+  ash::Shell::Get()->assistant_controller()->ui_controller()->ShowUi(
+      ash::AssistantSource::kLauncherSearchBox);
+}
+
 void AppListControllerImpl::StartSearch(const base::string16& raw_query) {
   last_raw_query_ = raw_query;
   if (client_) {
@@ -734,4 +759,11 @@ void AppListControllerImpl::UpdateHomeLauncherVisibility() {
     presenter_.GetWindow()->Show();
 }
 
+void AppListControllerImpl::UpdateAssistantVisibility() {
+  auto* controller = Shell::Get()->voice_interaction_controller();
+  GetSearchModel()->search_box()->SetShowAssistantButton(
+      controller->settings_enabled() &&
+      controller->allowed_state() == mojom::AssistantAllowedState::ALLOWED);
+}
+
 }  // namespace ash

ash/app_list/app_list_controller_impl.h

@@ -18,6 +18,7 @@
 #include "ash/ash_export.h"
 #include "ash/public/cpp/app_list/app_list_constants.h"
 #include "ash/public/interfaces/app_list.mojom.h"
+#include "ash/public/interfaces/voice_interaction_controller.mojom.h"
 #include "ash/session/session_observer.h"
 #include "ash/shell_observer.h"
 #include "ash/wallpaper/wallpaper_controller_observer.h"
@@ -48,7 +49,8 @@ class ASH_EXPORT AppListControllerImpl
       public ash::ShellObserver,
       public TabletModeObserver,
       public keyboard::KeyboardControllerObserver,
-      public WallpaperControllerObserver {
+      public WallpaperControllerObserver,
+      public mojom::VoiceInteractionObserver {
  public:
   using AppListItemMetadataPtr = mojom::AppListItemMetadataPtr;
   using SearchResultMetadataPtr = mojom::SearchResultMetadataPtr;
@@ -137,6 +139,7 @@ class ASH_EXPORT AppListControllerImpl
   // app_list::AppListViewDelegate:
   app_list::AppListModel* GetModel() override;
   app_list::SearchModel* GetSearchModel() override;
+  void StartAssistant() override;
   void StartSearch(const base::string16& raw_query) override;
   void OpenSearchResult(const std::string& result_id, int event_flags) override;
   void InvokeSearchResultAction(const std::string& result_id,
@@ -185,6 +188,16 @@ class ASH_EXPORT AppListControllerImpl
   void OnWallpaperPreviewStarted() override;
   void OnWallpaperPreviewEnded() override;
 
+  // mojom::VoiceInteractionObserver:
+  void OnVoiceInteractionStatusChanged(
+      mojom::VoiceInteractionState state) override {}
+  void OnVoiceInteractionSettingsEnabled(bool enabled) override;
+  void OnVoiceInteractionContextEnabled(bool enabled) override {}
+  void OnVoiceInteractionHotwordEnabled(bool enabled) override {}
+  void OnVoiceInteractionSetupCompleted(bool completed) override {}
+  void OnAssistantFeatureAllowedChanged(
+      mojom::AssistantAllowedState state) override;
+
   bool onscreen_keyboard_shown() const { return onscreen_keyboard_shown_; }
 
   // Returns true if the home launcher is enabled in tablet mode.
@@ -200,6 +213,9 @@ class ASH_EXPORT AppListControllerImpl
   // in overview mode.
   void UpdateHomeLauncherVisibility();
 
+  // Update the visibility of Assistant functionality.
+  void UpdateAssistantVisibility();
+
   base::string16 last_raw_query_;
 
   mojom::AppListClientPtr client_;
@@ -232,6 +248,8 @@ class ASH_EXPORT AppListControllerImpl
   // should be hidden during wallpaper preview.
   bool in_wallpaper_preview_ = false;
 
+  mojo::Binding<mojom::VoiceInteractionObserver> voice_interaction_binding_;
+
   DISALLOW_COPY_AND_ASSIGN(AppListControllerImpl);
 };
 

ash/app_list/app_list_view_delegate.h

@@ -32,6 +32,9 @@ class ASH_PUBLIC_EXPORT AppListViewDelegate {
   // owned by the delegate, or owned elsewhere (e.g. a profile keyed service).
   virtual SearchModel* GetSearchModel() = 0;
 
+  // Invoked to start a new Google Assistant session.
+  virtual void StartAssistant() = 0;
+
   // Invoked to start a new search. This collects a list of search results
   // matching the raw query, which is an unhandled string typed into the search
   // box by the user.

ash/app_list/model/search/search_box_model.cc

@@ -57,6 +57,14 @@ void SearchBoxModel::SetTabletMode(bool is_tablet_mode) {
   UpdateAccessibleName();
 }
 
+void SearchBoxModel::SetShowAssistantButton(bool show) {
+  if (show_assistant_button_ == show)
+    return;
+  show_assistant_button_ = show;
+  for (auto& observer : observers_)
+    observer.ShowAssistantChanged();
+}
+
 void SearchBoxModel::SetSearchEngineIsGoogle(bool is_google) {
   if (is_google == search_engine_is_google_)
     return;

ash/app_list/model/search/search_box_model.h

@@ -52,6 +52,9 @@ class APP_LIST_MODEL_EXPORT SearchBoxModel {
   void SetTabletMode(bool is_tablet_mode);
   bool is_tablet_mode() const { return is_tablet_mode_; }
 
+  void SetShowAssistantButton(bool show);
+  bool show_assistant_button() const { return show_assistant_button_; }
+
   void SetSearchEngineIsGoogle(bool is_google);
   bool search_engine_is_google() const { return search_engine_is_google_; }
 
@@ -73,6 +76,7 @@ class APP_LIST_MODEL_EXPORT SearchBoxModel {
   base::string16 text_;
   bool search_engine_is_google_ = false;
   bool is_tablet_mode_ = false;
+  bool show_assistant_button_ = false;
 
   base::ObserverList<SearchBoxModelObserver> observers_;
 

ash/app_list/model/search/search_box_model_observer.h

@@ -23,6 +23,9 @@ class APP_LIST_MODEL_EXPORT SearchBoxModelObserver {
   // Invoked when the search engine is changed.
   virtual void SearchEngineChanged() = 0;
 
+  // Invoked when whether to show Assistant is changed.
+  virtual void ShowAssistantChanged() = 0;
+
  protected:
   virtual ~SearchBoxModelObserver() {}
 };

ash/app_list/test/app_list_test_view_delegate.h

@@ -48,6 +48,7 @@ class AppListTestViewDelegate : public AppListViewDelegate,
   // AppListViewDelegate overrides:
   AppListModel* GetModel() override;
   SearchModel* GetSearchModel() override;
+  void StartAssistant() override {}
   void StartSearch(const base::string16& raw_query) override {}
   void OpenSearchResult(const std::string& result_id, int event_flags) override;
   void InvokeSearchResultAction(const std::string& result_id,

ash/app_list/views/app_list_main_view.cc

@@ -28,6 +28,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/string_util.h"
+#include "chromeos/chromeos_switches.h"
 #include "ui/chromeos/search_box/search_box_view_base.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/views/border.h"
@@ -192,6 +193,11 @@ void AppListMainView::ActiveChanged(search_box::SearchBoxViewBase* sender) {
   }
 }
 
+void AppListMainView::AssistantButtonPressed() {
+  DCHECK(chromeos::switches::IsAssistantEnabled());
+  delegate_->StartAssistant();
+}
+
 void AppListMainView::BackButtonPressed() {
   if (!contents_view_->Back())
     app_list_view_->Dismiss();

ash/app_list/views/app_list_main_view.h

@@ -90,6 +90,7 @@ class APP_LIST_EXPORT AppListMainView
 
   // Overridden from SearchBoxViewDelegate:
   void QueryChanged(search_box::SearchBoxViewBase* sender) override;
+  void AssistantButtonPressed() override;
   void BackButtonPressed() override;
   void ActiveChanged(search_box::SearchBoxViewBase* sender) override;
 

ash/app_list/views/search_box_view.cc

@@ -23,9 +23,11 @@
 #include "ash/public/cpp/app_list/app_list_constants.h"
 #include "ash/public/cpp/app_list/app_list_features.h"
 #include "ash/public/cpp/app_list/vector_icons/vector_icons.h"
+#include "ash/public/cpp/vector_icons/vector_icons.h"
 #include "ash/public/cpp/wallpaper_types.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
+#include "chromeos/chromeos_switches.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/chromeos/search_box/search_box_constants.h"
@@ -59,6 +61,7 @@ constexpr SkColor kSearchBoxBorderColor =
     SkColorSetARGB(0x3D, 0xFF, 0xFF, 0xFF);
 
 constexpr int kSearchBoxBorderCornerRadiusSearchResult = 4;
+constexpr int kAssistantIconSize = 24;
 constexpr int kCloseIconSize = 24;
 constexpr int kSearchBoxFocusBorderCornerRadius = 28;
 
@@ -77,6 +80,12 @@ int GetBoxLayoutPaddingForState(ash::AppListState state) {
   return search_box::kPadding;
 }
 
+float GetAssistantButtonOpacityForState(ash::AppListState state) {
+  if (state == ash::AppListState::kStateSearchResults)
+    return .0f;
+  return 1.f;
+}
+
 }  // namespace
 
 SearchBoxView::SearchBoxView(search_box::SearchBoxViewDelegate* delegate,
@@ -130,6 +139,7 @@ void SearchBoxView::ModelChanged() {
 
   HintTextChanged();
   OnWallpaperColorsChanged();
+  ShowAssistantChanged();
 }
 
 void SearchBoxView::UpdateKeyboardVisibility() {
@@ -276,9 +286,16 @@ void SearchBoxView::UpdateLayout(double progress,
                                  ash::AppListState current_state,
                                  ash::AppListState target_state) {
   box_layout()->set_inside_border_insets(
-      gfx::Insets(0, gfx::Tween::LinearIntValueBetween(
-                         progress, GetBoxLayoutPaddingForState(current_state),
-                         GetBoxLayoutPaddingForState(target_state))));
+      gfx::Insets(0,
+                  gfx::Tween::LinearIntValueBetween(
+                      progress, GetBoxLayoutPaddingForState(current_state),
+                      GetBoxLayoutPaddingForState(target_state)),
+                  0, 0));
+  if (show_assistant_button()) {
+    assistant_button()->layer()->SetOpacity(gfx::Tween::LinearIntValueBetween(
+        progress, GetAssistantButtonOpacityForState(current_state),
+        GetAssistantButtonOpacityForState(target_state)));
+  }
   InvalidateLayout();
 }
 
@@ -537,7 +554,7 @@ void SearchBoxView::SelectionModelChanged() {
 
 void SearchBoxView::Update() {
   search_box()->SetText(search_model_->search_box()->text());
-  UpdateCloseButtonVisisbility();
+  UpdateButtonsVisisbility();
   NotifyQueryChanged();
 }
 
@@ -545,4 +562,25 @@ void SearchBoxView::SearchEngineChanged() {
   UpdateSearchIcon();
 }
 
+void SearchBoxView::ShowAssistantChanged() {
+  if (search_model_) {
+    SetShowAssistantButton(
+        search_model_->search_box()->show_assistant_button());
+  }
+}
+
+void SearchBoxView::SetupAssistantButton() {
+  if (search_model_ && !search_model_->search_box()->show_assistant_button()) {
+    return;
+  }
+
+  views::ImageButton* assistant = assistant_button();
+  assistant->SetImage(
+      views::ImageButton::STATE_NORMAL,
+      gfx::CreateVectorIcon(ash::kAssistantIcon, kAssistantIconSize,
+                            search_box_color()));
+  assistant->SetAccessibleName(
+      l10n_util::GetStringUTF16(IDS_APP_LIST_START_ASSISTANT));
+}
+
 }  // namespace app_list

ash/app_list/views/search_box_view.h

@@ -46,6 +46,7 @@ class APP_LIST_EXPORT SearchBoxView : public search_box::SearchBoxViewBase,
   void UpdateModel(bool initiated_by_user) override;
   void UpdateSearchIcon() override;
   void UpdateSearchBoxBorder() override;
+  void SetupAssistantButton() override;
   void SetupCloseButton() override;
   void SetupBackButton() override;
   void RecordSearchBoxActivationHistogram(ui::EventType event_type) override;
@@ -127,6 +128,7 @@ class APP_LIST_EXPORT SearchBoxView : public search_box::SearchBoxViewBase,
   void SelectionModelChanged() override;
   void Update() override;
   void SearchEngineChanged() override;
+  void ShowAssistantChanged() override;
 
   // The range of highlighted text for autocomplete.
   gfx::Range highlight_range_;

ash/app_list/views/search_box_view_unittest.cc

@@ -151,6 +151,7 @@ class SearchBoxViewTest : public views::test::WidgetTest,
     last_query_ = sender->search_box()->text();
   }
 
+  void AssistantButtonPressed() override {}
   void BackButtonPressed() override {}
   void ActiveChanged(search_box::SearchBoxViewBase* sender) override {}
 

ash/assistant/model/assistant_ui_model.h

@@ -21,6 +21,7 @@ enum class AssistantSource {
   kLongPressLauncher,
   kSetup,
   kStylus,
+  kLauncherSearchBox,
 };
 
 // Enumeration of Assistant UI modes.

ash/assistant/ui/assistant_mini_view.cc

@@ -4,6 +4,7 @@
 
 #include "ash/assistant/ui/assistant_mini_view.h"
 
+#include <algorithm>
 #include <memory>
 
 #include "ash/assistant/assistant_controller.h"
@@ -11,7 +12,7 @@
 #include "ash/assistant/assistant_ui_controller.h"
 #include "ash/assistant/model/assistant_query.h"
 #include "ash/assistant/ui/assistant_ui_constants.h"
-#include "ash/resources/vector_icons/vector_icons.h"
+#include "ash/public/cpp/vector_icons/vector_icons.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/l10n/l10n_util.h"

ash/components/shortcut_viewer/views/keyboard_shortcut_view.h

@@ -62,6 +62,7 @@ class KeyboardShortcutView : public views::WidgetDelegateView,
 
   // search_box::SearchBoxViewDelegate:
   void QueryChanged(search_box::SearchBoxViewBase* sender) override;
+  void AssistantButtonPressed() override {}
   void BackButtonPressed() override;
   void ActiveChanged(search_box::SearchBoxViewBase* sender) override;
 

ash/components/shortcut_viewer/views/ksv_search_box_view.h

@@ -39,6 +39,7 @@ class KSVSearchBoxView : public search_box::SearchBoxViewBase {
   void UpdateModel(bool initiated_by_user) override {}
   void UpdateSearchIcon() override {}
   void UpdateSearchBoxBorder() override;
+  void SetupAssistantButton() override {}
   void SetupCloseButton() override;
   void SetupBackButton() override;
 

ash/public/cpp/vector_icons/BUILD.gn

@@ -9,6 +9,7 @@ aggregate_vector_icons("ash_public_vector_icons") {
   icon_directory = "."
 
   icons = [
+    "assistant.icon",
     "notification_assistant.icon",
     "notification_captive_portal.icon",
     "notification_cellular_alert.icon",

ash/resources/vector_icons/BUILD.gn

@@ -9,7 +9,6 @@ aggregate_vector_icons("ash_vector_icons") {
   icon_directory = "."
 
   icons = [
-    "assistant.icon",
     "auto_hide.icon",
     "captive_portal.icon",
     "check_circle.icon",

ash/shell.cc

@@ -1108,6 +1108,8 @@ void Shell::Init(
       display::Screen::GetScreen()->GetPrimaryDisplay());
 
   accelerator_controller_ = std::make_unique<AcceleratorController>(nullptr);
+  voice_interaction_controller_ =
+      std::make_unique<VoiceInteractionController>();
 
   // |app_list_controller_| is put after |tablet_mode_controller_| as the former
   // uses the latter in constructor.
@@ -1185,8 +1187,6 @@ void Shell::Init(
   laser_pointer_controller_.reset(new LaserPointerController());
   partial_magnification_controller_.reset(new PartialMagnificationController());
   highlighter_controller_.reset(new HighlighterController());
-  voice_interaction_controller_ =
-      std::make_unique<VoiceInteractionController>();
 
   assistant_controller_ = chromeos::switches::IsAssistantEnabled()
                               ? std::make_unique<AssistantController>()

ash/shell/app_list.cc

@@ -235,6 +235,8 @@ class ExampleAppListViewDelegate : public app_list::AppListViewDelegate {
     NOTIMPLEMENTED();
   }
 
+  void StartAssistant() override { NOTIMPLEMENTED(); }
+
   void StartSearch(const base::string16& raw_query) override {
     base::string16 query;
     base::TrimWhitespace(raw_query, base::TRIM_ALL, &query);

ui/chromeos/search_box/search_box_view_base.cc

@@ -14,9 +14,14 @@
 #include "ui/chromeos/search_box/search_box_view_delegate.h"
 #include "ui/events/event.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/color_palette.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/image/image_skia.h"
+#include "ui/views/animation/flood_fill_ink_drop_ripple.h"
+#include "ui/views/animation/ink_drop_highlight.h"
+#include "ui/views/animation/ink_drop_impl.h"
+#include "ui/views/animation/ink_drop_mask.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/context_menu_controller.h"
@@ -34,6 +39,8 @@ namespace {
 
 constexpr int kInnerPadding = 16;
 
+constexpr int kButtonSizeDip = 48;
+
 // Preferred width of search box.
 constexpr int kSearchBoxPreferredWidth = 544;
 
@@ -88,6 +95,14 @@ class SearchBoxImageButton : public views::ImageButton {
     // Avoid drawing default dashed focus and draw customized focus in
     // OnPaintBackground();
     SetFocusPainter(nullptr);
+
+    SetPaintToLayer();
+    layer()->SetFillsBoundsOpaquely(false);
+    SetInkDropMode(InkDropMode::ON);
+
+    SetPreferredSize({kButtonSizeDip, kButtonSizeDip});
+    SetImageAlignment(HorizontalAlignment::ALIGN_CENTER,
+                      VerticalAlignment::ALIGN_MIDDLE);
   }
   ~SearchBoxImageButton() override {}
 
@@ -107,11 +122,49 @@ class SearchBoxImageButton : public views::ImageButton {
 
   void OnBlur() override { SchedulePaint(); }
 
+  // views::InkDropHost overrides:
+  std::unique_ptr<views::InkDrop> CreateInkDrop() override {
+    return CreateDefaultFloodFillInkDropImpl();
+  }
+
+  std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override {
+    const gfx::Point center = GetLocalBounds().CenterPoint();
+    const int ripple_radius = GetInkDropRadius();
+    gfx::Rect bounds(center.x() - ripple_radius, center.y() - ripple_radius,
+                     2 * ripple_radius, 2 * ripple_radius);
+    constexpr SkColor ripple_color = SkColorSetA(gfx::kGoogleGrey900, 0x17);
+
+    return std::make_unique<views::FloodFillInkDropRipple>(
+        size(), GetLocalBounds().InsetsFrom(bounds),
+        GetInkDropCenterBasedOnLastEvent(), ripple_color, 1.0f);
+  }
+
+  std::unique_ptr<views::InkDropMask> CreateInkDropMask() const override {
+    return std::make_unique<views::CircleInkDropMask>(
+        size(), GetLocalBounds().CenterPoint(), GetInkDropRadius());
+  }
+
+  std::unique_ptr<views::InkDropHighlight> CreateInkDropHighlight()
+      const override {
+    constexpr SkColor ripple_color = SkColorSetA(gfx::kGoogleGrey900, 0x12);
+    return std::make_unique<views::InkDropHighlight>(
+        gfx::PointF(GetLocalBounds().CenterPoint()),
+        std::make_unique<views::CircleLayerDelegate>(ripple_color,
+                                                     GetInkDropRadius()));
+  }
+
  private:
+  int GetInkDropRadius() const { return width() / 2; }
+
   // views::View overrides:
   void OnPaintBackground(gfx::Canvas* canvas) override {
-    if (state() == STATE_PRESSED || HasFocus()) {
-      canvas->FillRect(gfx::Rect(size()), kSelectedColor);
+    if (HasFocus()) {
+      cc::PaintFlags circle_flags;
+      circle_flags.setAntiAlias(true);
+      circle_flags.setColor(kSelectedColor);
+      circle_flags.setStyle(cc::PaintFlags::kFill_Style);
+      canvas->DrawCircle(GetLocalBounds().CenterPoint(), GetInkDropRadius(),
+                         circle_flags);
     }
   }
 
@@ -184,7 +237,7 @@ SearchBoxViewBase::SearchBoxViewBase(SearchBoxViewDelegate* delegate)
 
   search_box_->SetBorder(views::NullBorder());
   search_box_->SetTextColor(kSearchTextColor);
-  search_box_->SetBackgroundColor(background_color_);
+  search_box_->SetBackgroundColor(SK_ColorTRANSPARENT);
   search_box_->set_controller(this);
   search_box_->SetTextInputType(ui::TEXT_INPUT_TYPE_SEARCH);
   search_box_->SetTextInputFlags(ui::TEXT_INPUT_FLAG_AUTOCORRECT_OFF);
@@ -207,6 +260,11 @@ SearchBoxViewBase::SearchBoxViewBase(SearchBoxViewDelegate* delegate)
   search_box_right_space_->SetPreferredSize(gfx::Size(kSearchIconSize, 0));
   content_container_->AddChildView(search_box_right_space_);
 
+  assistant_button_ = new SearchBoxImageButton(this);
+  // Default hidden, child class should decide if it should shown.
+  assistant_button_->SetVisible(false);
+  content_container_->AddChildView(assistant_button_);
+
   close_button_ = new SearchBoxImageButton(this);
   content_container_->AddChildView(close_button_);
 }
@@ -218,6 +276,7 @@ void SearchBoxViewBase::Init() {
   layer()->SetFillsBoundsOpaquely(false);
   layer()->SetMasksToBounds(true);
   UpdateSearchBoxBorder();
+  SetupAssistantButton();
   SetupBackButton();
   SetupCloseButton();
   ModelChanged();
@@ -234,6 +293,10 @@ gfx::Rect SearchBoxViewBase::GetViewBoundsForSearchBoxContentsBounds(
   return view_bounds;
 }
 
+views::ImageButton* SearchBoxViewBase::assistant_button() {
+  return static_cast<views::ImageButton*>(assistant_button_);
+}
+
 views::ImageButton* SearchBoxViewBase::back_button() {
   return static_cast<views::ImageButton*>(back_button_);
 }
@@ -275,7 +338,7 @@ void SearchBoxViewBase::SetSearchBoxActive(bool active,
 
   UpdateSearchBoxBorder();
   UpdateKeyboardVisibility();
-  UpdateCloseButtonVisisbility();
+  UpdateButtonsVisisbility();
 
   NotifyActiveChanged();
 
@@ -331,7 +394,9 @@ bool SearchBoxViewBase::ShouldAdvanceFocusToTopLevelWidget() const {
 
 void SearchBoxViewBase::ButtonPressed(views::Button* sender,
                                       const ui::Event& event) {
-  if (back_button_ && sender == back_button_) {
+  if (assistant_button_ && sender == assistant_button_) {
+    delegate_->AssistantButtonPressed();
+  } else if (back_button_ && sender == back_button_) {
     delegate_->BackButtonPressed();
   } else if (close_button_ && sender == close_button_) {
     ClearSearch();
@@ -360,7 +425,7 @@ bool SearchBoxViewBase::IsSearchBoxTrimmedQueryEmpty() const {
 
 void SearchBoxViewBase::ClearSearch() {
   search_box_->SetText(base::string16());
-  UpdateCloseButtonVisisbility();
+  UpdateButtonsVisisbility();
   // Updates model and fires query changed manually because SetText() above
   // does not generate ContentsChanged() notification.
   UpdateModel(false);
@@ -395,15 +460,22 @@ void SearchBoxViewBase::SetSearchBoxColor(SkColor color) {
       SK_ColorTRANSPARENT == color ? kDefaultSearchboxColor : color;
 }
 
-void SearchBoxViewBase::UpdateCloseButtonVisisbility() {
-  if (!close_button_)
-    return;
-  bool should_show_close_button_ =
+void SearchBoxViewBase::UpdateButtonsVisisbility() {
+  DCHECK(close_button_ && assistant_button_);
+
+  bool should_show_close_button =
       !search_box_->text().empty() ||
       (show_close_button_when_active_ && is_search_box_active_);
-  if (close_button_->visible() == should_show_close_button_)
+  bool should_show_assistant_button =
+      show_assistant_button_ && !should_show_close_button;
+
+  if (close_button_->visible() == should_show_close_button &&
+      assistant_button_->visible() == should_show_assistant_button) {
     return;
-  close_button_->SetVisible(should_show_close_button_);
+  }
+
+  close_button_->SetVisible(should_show_close_button);
+  assistant_button_->SetVisible(should_show_assistant_button);
   content_container_->Layout();
 }
 
@@ -414,7 +486,7 @@ void SearchBoxViewBase::ContentsChanged(views::Textfield* sender,
   UpdateModel(true);
   NotifyQueryChanged();
   SetSearchBoxActive(true, ui::ET_KEY_PRESSED);
-  UpdateCloseButtonVisisbility();
+  UpdateButtonsVisisbility();
 }
 
 bool SearchBoxViewBase::HandleMouseEvent(views::Textfield* sender,
@@ -440,6 +512,11 @@ void SearchBoxViewBase::SetSearchIconImage(gfx::ImageSkia image) {
   search_icon_->SetImage(image);
 }
 
+void SearchBoxViewBase::SetShowAssistantButton(bool show) {
+  show_assistant_button_ = show;
+  UpdateButtonsVisisbility();
+}
+
 void SearchBoxViewBase::HandleSearchBoxEvent(ui::LocatedEvent* located_event) {
   if (located_event->type() == ui::ET_MOUSE_PRESSED ||
       located_event->type() == ui::ET_GESTURE_TAP) {
@@ -462,7 +539,6 @@ void SearchBoxViewBase::UpdateBackgroundColor(SkColor color) {
   if (is_search_box_active_)
     color = kSearchBoxBackgroundDefault;
   GetSearchBoxBackground()->set_color(color);
-  search_box_->SetBackgroundColor(color);
 }
 
 SearchBoxBackground* SearchBoxViewBase::GetSearchBoxBackground() const {

ui/chromeos/search_box/search_box_view_base.h

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_
-#define UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_
+#ifndef UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_
+#define UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_
 
 #include <vector>
 
@@ -66,6 +66,7 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
   gfx::Rect GetViewBoundsForSearchBoxContentsBounds(
       const gfx::Rect& rect) const;
 
+  views::ImageButton* assistant_button();
   views::ImageButton* back_button();
   views::ImageButton* close_button();
   views::Textfield* search_box() { return search_box_; }
@@ -113,6 +114,8 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
     show_close_button_when_active_ = show_button;
   }
 
+  bool show_assistant_button() { return show_assistant_button_; }
+
   void OnOnSearchBoxFocusedChanged();
 
   // Whether the trimmed query in the search box is empty.
@@ -139,7 +142,7 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
   SkColor search_box_color() const { return search_box_color_; }
 
   // Updates the visibility of close button.
-  void UpdateCloseButtonVisisbility();
+  void UpdateButtonsVisisbility();
 
   // Overridden from views::TextfieldController:
   void ContentsChanged(views::Textfield* sender,
@@ -161,6 +164,8 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
 
   void SetSearchIconImage(gfx::ImageSkia image);
 
+  void SetShowAssistantButton(bool show);
+
   // Detects |ET_MOUSE_PRESSED| and |ET_GESTURE_TAP| events on the white
   // background of the search box.
   virtual void HandleSearchBoxEvent(ui::LocatedEvent* located_event);
@@ -184,11 +189,12 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
   virtual void UpdateSearchBoxBorder() = 0;
 
   // Setup button's image, accessible name, and tooltip text etc.
+  virtual void SetupAssistantButton() = 0;
   virtual void SetupCloseButton() = 0;
   virtual void SetupBackButton() = 0;
 
   // Records in histograms the activation of the searchbox.
-  virtual void RecordSearchBoxActivationHistogram(ui::EventType event_type){};
+  virtual void RecordSearchBoxActivationHistogram(ui::EventType event_type) {}
 
   // Gets the search box background.
   SearchBoxBackground* GetSearchBoxBackground() const;
@@ -198,6 +204,7 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
   // Owned by views hierarchy.
   views::View* content_container_;
   views::ImageView* search_icon_ = nullptr;
+  SearchBoxImageButton* assistant_button_ = nullptr;
   SearchBoxImageButton* back_button_ = nullptr;
   SearchBoxImageButton* close_button_ = nullptr;
   views::Textfield* search_box_;
@@ -210,6 +217,8 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
   bool is_search_box_active_ = false;
   // Whether to show close button if the search box is active.
   bool show_close_button_when_active_ = false;
+  // Whether to show assistant button.
+  bool show_assistant_button_ = false;
   // Whether tablet mode is active.
   bool is_tablet_mode_ = false;
   // The current background color.
@@ -222,4 +231,4 @@ class SEARCH_BOX_EXPORT SearchBoxViewBase : public views::WidgetDelegateView,
 
 }  // namespace search_box
 
-#endif  // UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_
+#endif  // UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_BASE_H_

ui/chromeos/search_box/search_box_view_delegate.h

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_
-#define UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_
+#ifndef UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_
+#define UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_
 
 #include "ui/chromeos/search_box/search_box_export.h"
 
@@ -16,6 +16,9 @@ class SEARCH_BOX_EXPORT SearchBoxViewDelegate {
   // Invoked when query text has changed by the user.
   virtual void QueryChanged(SearchBoxViewBase* sender) = 0;
 
+  // Invoked when the back button has been pressed.
+  virtual void AssistantButtonPressed() = 0;
+
   // Invoked when the back button has been pressed.
   virtual void BackButtonPressed() = 0;
 
@@ -28,4 +31,4 @@ class SEARCH_BOX_EXPORT SearchBoxViewDelegate {
 
 }  // namespace search_box
 
-#endif  // UI_CHOMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_
+#endif  // UI_CHROMEOS_SEARCH_BOX_SEARCH_BOX_VIEW_DELEGATE_H_

ui/strings/ui_strings.grd

@@ -794,6 +794,9 @@ need to be translated for each locale.-->
       <message name="IDS_APP_LIST_CLEAR_SEARCHBOX" desc="Tooltip for the button that clears all text from the search box in the app list.">
         Clear searchbox text
       </message>
+      <message name="IDS_APP_LIST_START_ASSISTANT" desc="Tooltip for the button that starts Google Assistant from the search box in the app list.">
+        Start Google Assistant
+      </message>
       <message name="IDS_APP_LIST_PAGE_SWITCHER" desc="Tooltip for page switcher for each page in fullscreen view which shows all apps.">
         Page <ph name="selected_page">$1<ex>1</ex></ph> of <ph name="total_page_num">$2<ex>3</ex></ph>
       </message>