CrOS shelf: permanent background behind back + launcher buttons

Replace the logic in ShelfView's overridden OnPaint with a simpler
view and rounded corners.

You can see a screenshot in comment #17 of the linked bug.

Bug: 874161
Change-Id: I416e670ca578e6fd5d4e7681c8c19acf2fa17c3a
Reviewed-on: https://chromium-review.googlesource.com/1198525Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Manu Cornet <manucornet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588220}

ash/shelf/app_list_button.cc

@@ -70,7 +70,6 @@ AppListButton::AppListButton(InkDropButtonListener* listener,
   Shell::Get()->AddShellObserver(this);
   Shell::Get()->session_controller()->AddObserver(this);
 
-  const int shelf_size = ShelfConstants::shelf_size();
   mojom::VoiceInteractionObserverPtr ptr;
   voice_interaction_binding_.Bind(mojo::MakeRequest(&ptr));
   Shell::Get()->voice_interaction_controller()->AddObserver(std::move(ptr));
@@ -79,7 +78,7 @@ AppListButton::AppListButton(InkDropButtonListener* listener,
   set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);
   SetAccessibleName(
       l10n_util::GetStringUTF16(IDS_ASH_SHELF_APP_LIST_LAUNCHER_TITLE));
-  SetSize(gfx::Size(shelf_size, shelf_size));
+  SetSize(gfx::Size(kShelfControlSizeNewUi, kShelfControlSizeNewUi));
   SetFocusPainter(TrayPopupUtils::CreateFocusPainter());
   set_notify_action(Button::NOTIFY_ON_PRESS);
 

ash/shelf/back_button.cc

@@ -33,9 +33,8 @@ BackButton::BackButton() : views::ImageButton(nullptr) {
   set_ink_drop_base_color(kShelfInkDropBaseColor);
   set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);
 
-  const int shelf_size = ShelfConstants::shelf_size();
   SetAccessibleName(l10n_util::GetStringUTF16(IDS_ASH_SHELF_BACK_BUTTON_TITLE));
-  SetSize(gfx::Size(shelf_size, shelf_size));
+  SetSize(gfx::Size(kShelfControlSizeNewUi, kShelfControlSizeNewUi));
   SetFocusPainter(TrayPopupUtils::CreateFocusPainter());
 }
 

ash/shelf/shelf_view.cc

@@ -366,6 +366,18 @@ ShelfView::~ShelfView() {
 void ShelfView::Init() {
   model_->AddObserver(this);
 
+  // Add the background view behind the app list and back buttons first, so
+  // that other views will appear above it.
+  if (chromeos::switches::ShouldUseShelfNewUi()) {
+    back_and_app_list_background_ = new views::View();
+    back_and_app_list_background_->SetBackground(
+        CreateBackgroundFromPainter(views::Painter::CreateSolidRoundRectPainter(
+            kShelfControlPermanentHighlightBackground,
+            ShelfConstants::control_border_radius())));
+    ConfigureChildView(back_and_app_list_background_);
+    AddChildView(back_and_app_list_background_);
+  }
+
   const ShelfItems& items(model_->items());
   for (ShelfItems::const_iterator i = items.begin(); i != items.end(); ++i) {
     views::View* child = CreateViewForItem(*i);
@@ -1006,6 +1018,20 @@ void ShelfView::CalculateIdealBounds(gfx::Rect* overflow_bounds) const {
     if (i == kAppListButtonIndex) {
       app_list_button_position = shelf_->PrimaryAxisValue(x, y);
       if (chromeos::switches::ShouldUseShelfNewUi()) {
+        // "Secondary" as in "orthogonal to the shelf primary axis".
+        const int control_secondary_padding =
+            (ShelfConstants::shelf_size() - kShelfControlSizeNewUi) / 2;
+        const int back_and_app_list_background_size =
+            kShelfControlSizeNewUi +
+            (IsTabletModeEnabled() ? kShelfControlSizeNewUi + 2 * button_spacing
+                                   : 0);
+        back_and_app_list_background_->SetBounds(
+            shelf_->PrimaryAxisValue(button_spacing, control_secondary_padding),
+            shelf_->PrimaryAxisValue(control_secondary_padding, button_spacing),
+            shelf_->PrimaryAxisValue(back_and_app_list_background_size,
+                                     kShelfControlSizeNewUi),
+            shelf_->PrimaryAxisValue(kShelfControlSizeNewUi,
+                                     back_and_app_list_background_size));
         // In the new UI, a larger minimum padding after the app list button
         // is required: increment with the necessary extra amount.
         x += shelf_->PrimaryAxisValue(kAppListButtonMargin - button_spacing, 0);
@@ -1740,41 +1766,6 @@ void ShelfView::OnBoundsChanged(const gfx::Rect& previous_bounds) {
     overflow_bubble_->Hide();
 }
 
-void ShelfView::OnPaint(gfx::Canvas* canvas) {
-  if (overflow_mode_)
-    return;
-
-  const int app_list_button_radius = ShelfConstants::app_list_button_radius();
-  cc::PaintFlags flags;
-  flags.setColor(shelf_item_background_color_);
-  flags.setAntiAlias(true);
-  flags.setStyle(cc::PaintFlags::kFill_Style);
-
-  // Draws a round rect around the back button and app list button. This will
-  // just be a circle if the back button is hidden.
-  const gfx::PointF circle_center(
-      GetMirroredRect(GetAppListButton()->bounds()).origin() +
-      gfx::Vector2d(GetAppListButton()->GetCenterPoint().x(),
-                    GetAppListButton()->GetCenterPoint().y()));
-  if (GetBackButton()->layer()->opacity() <= 0.f) {
-    canvas->DrawCircle(circle_center, app_list_button_radius, flags);
-    return;
-  }
-
-  const int button_size = ShelfConstants::button_size();
-  const gfx::PointF back_center(
-      GetMirroredRect(GetBackButton()->bounds()).x() + button_size / 2,
-      GetBackButton()->bounds().y() + button_size / 2);
-  const gfx::RectF background_bounds(
-      std::min(back_center.x(), circle_center.x()) - app_list_button_radius,
-      back_center.y() - app_list_button_radius,
-      std::abs(circle_center.x() - back_center.x()) +
-          2 * app_list_button_radius,
-      2 * app_list_button_radius);
-
-  canvas->DrawRoundRect(background_bounds, app_list_button_radius, flags);
-}
-
 views::FocusTraversable* ShelfView::GetPaneFocusTraversable() {
   return this;
 }

ash/shelf/shelf_view.h

@@ -383,7 +383,6 @@ class ASH_EXPORT ShelfView : public views::View,
   // Overridden from views::View:
   gfx::Size CalculatePreferredSize() const override;
   void OnBoundsChanged(const gfx::Rect& previous_bounds) override;
-  void OnPaint(gfx::Canvas* canvas) override;
   FocusTraversable* GetPaneFocusTraversable() override;
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
   void ViewHierarchyChanged(
@@ -585,7 +584,11 @@ class ASH_EXPORT ShelfView : public views::View,
 
   // A reference to the view used as a separator between pinned and unpinned
   // items.
-  views::Separator* separator_;
+  views::Separator* separator_ = nullptr;
+
+  // A view to draw a background behind the app list and back buttons.
+  // Owned by the view hierarchy.
+  views::View* back_and_app_list_background_ = nullptr;
 
   base::WeakPtrFactory<ShelfView> weak_factory_;