CrOS Shelf: Change hotseat color between in-app and home shelf.

In this change, the hotseat background will change color for different
shelf states and will animate between colors when changing. When in-app
shelf is shown the hotseat color should have an alpha value of 90%.
When the home shelf is shown the hotseat color should have an alpha
value of 60%.

Bug: 1041132
Change-Id: I9459fbb61cbc538029039cd48c04144a98ab82c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003919Reviewed-by: Manu Cornet <manucornet@chromium.org>
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734159}

ash/shelf/hotseat_widget.cc

@@ -126,6 +126,9 @@ class HotseatWidget::DelegateView : public views::WidgetDelegateView,
   // The WallpaperController, responsible for providing proper colors.
   WallpaperControllerImpl* wallpaper_controller_;
 
+  // The most recent color that the |opaque_background_| has been animated to.
+  SkColor target_color_;
+
   DISALLOW_COPY_AND_ASSIGN(DelegateView);
 };
 
@@ -167,7 +170,20 @@ void HotseatWidget::DelegateView::SetOpaqueBackground(
   DCHECK(HotseatWidget::ShouldShowHotseatBackground());
 
   opaque_background_.SetVisible(true);
-  opaque_background_.SetColor(ShelfConfig::Get()->GetDefaultShelfColor());
+
+  if (ShelfConfig::Get()->GetDefaultShelfColor() != target_color_) {
+    target_color_ = ShelfConfig::Get()->GetDefaultShelfColor();
+
+    ui::ScopedLayerAnimationSettings animation_setter(
+        opaque_background_.GetAnimator());
+    animation_setter.SetTransitionDuration(
+        ShelfConfig::Get()->shelf_animation_duration());
+    animation_setter.SetTweenType(gfx::Tween::EASE_OUT);
+    animation_setter.SetPreemptionStrategy(
+        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+
+    opaque_background_.SetColor(target_color_);
+  }
 
   const int radius = ShelfConfig::Get()->hotseat_size() / 2;
   gfx::RoundedCornersF rounded_corners = {radius, radius, radius, radius};

ash/shelf/shelf_config.cc

@@ -304,10 +304,20 @@ SkColor ShelfConfig::GetDefaultShelfColor() const {
         AshColorProvider::AshColorMode::kDark);
   }
 
+  AshColorProvider::BaseLayerType layer_type;
+  if (!chromeos::switches::ShouldShowShelfHotseat()) {
+    layer_type = IsTabletMode()
+                     ? AshColorProvider::BaseLayerType::kTransparent60
+                     : AshColorProvider::BaseLayerType::kTransparent74;
+  } else if (IsTabletMode()) {
+    layer_type = is_in_app() ? AshColorProvider::BaseLayerType::kTransparent90
+                             : AshColorProvider::BaseLayerType::kTransparent60;
+  } else {
+    layer_type = AshColorProvider::BaseLayerType::kTransparent74;
+  }
+
   SkColor final_color = AshColorProvider::Get()->GetBaseLayerColor(
-      IsTabletMode() ? AshColorProvider::BaseLayerType::kTransparent60
-                     : AshColorProvider::BaseLayerType::kTransparent74,
-      AshColorProvider::AshColorMode::kDark);
+      layer_type, AshColorProvider::AshColorMode::kDark);
 
   return GetThemedColorFromWallpaper(final_color);
 }