Add bounce animation for tray background views

This CL refactors previous animations for tray background views
to use layer transforms and also adds a new bounce animation
to be used for holding space and screen recorder tray buttons.

Bug: 896739
Change-Id: I29ce064d44eda7ebb3b98f856ba9b2171be0c549
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2589454
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837029}

ash/system/holding_space/holding_space_tray.cc

@@ -95,6 +95,8 @@ HoldingSpaceTray::HoldingSpaceTray(Shelf* shelf) : TrayBackgroundView(shelf) {
   // the holding space model will already have been attached.
   if (HoldingSpaceController::Get()->model())
     OnHoldingSpaceModelAttached(HoldingSpaceController::Get()->model());
+
+  set_use_bounce_in_animation(true);
 }
 
 HoldingSpaceTray::~HoldingSpaceTray() = default;

ash/system/tray/tray_background_view.h

@@ -27,7 +27,7 @@ class TrayEventFilter;
 // inherits from ActionableView so that the tray items can override
 // PerformAction when clicked on.
 class ASH_EXPORT TrayBackgroundView : public ActionableView,
-                                      public ui::ImplicitAnimationObserver,
+                                      public ui::LayerAnimationObserver,
                                       public ShelfBackgroundAnimatorObserver,
                                       public TrayBubbleView::Delegate,
                                       public VirtualKeyboardModel::Observer {
@@ -153,6 +153,10 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
     show_with_virtual_keyboard_ = show_with_virtual_keyboard;
   }
 
+  void set_use_bounce_in_animation(bool use_bounce_in_animation) {
+    use_bounce_in_animation_ = use_bounce_in_animation;
+  }
+
  private:
   class TrayWidgetObserver;
 
@@ -165,12 +169,16 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   const char* GetClassName() const override;
 
   // ui::ImplicitAnimationObserver:
-  void OnImplicitAnimationsCompleted() override;
-  bool RequiresNotificationWhenAnimatorDestroyed() const override;
+  void OnLayerAnimationAborted(ui::LayerAnimationSequence* sequence) override {}
+  void OnLayerAnimationEnded(ui::LayerAnimationSequence* sequence) override;
+  void OnLayerAnimationScheduled(
+      ui::LayerAnimationSequence* sequence) override {}
 
   // Applies transformations to the |layer()| to animate the view when
   // SetVisible(false) is called.
-  void HideTransformation();
+  void HideAnimation();
+  void FadeInAnimation();
+  void BounceInAnimation();
 
   // Helper function that calculates background insets relative to local bounds.
   gfx::Insets GetBackgroundInsets() const;
@@ -204,6 +212,8 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // If true, the view is visible when the status area is collapsed.
   bool show_when_collapsed_;
 
+  bool use_bounce_in_animation_ = false;
+
   std::unique_ptr<TrayWidgetObserver> widget_observer_;
   std::unique_ptr<TrayEventFilter> tray_event_filter_;