Update the background color of ARC notifications when notification settings is opened.

ui/arc/notification/arc_custom_notification_view.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_
 #define UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "ui/arc/notification/arc_custom_notification_item.h"
 #include "ui/arc/notification/arc_notification_surface_manager.h"
 #include "ui/aura/window_observer.h"
+#include "ui/gfx/animation/animation_delegate.h"
 #include "ui/message_center/views/custom_notification_content_view_delegate.h"
 #include "ui/message_center/views/padded_button.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/native/native_view_host.h"
 
 namespace exo {
 class NotificationSurface;
 }
 
+namespace gfx {
+class LinearAnimation;
+}
+
 namespace views {
 class FocusTraversable;
 class Widget;
 }
 
 namespace arc {
 
 class ArcCustomNotificationView
     : public views::NativeViewHost,
       public views::ButtonListener,
       public aura::WindowObserver,
       public ArcCustomNotificationItem::Observer,
-      public ArcNotificationSurfaceManager::Observer {
+      public ArcNotificationSurfaceManager::Observer,
+      public gfx::AnimationDelegate {
  public:
   explicit ArcCustomNotificationView(ArcCustomNotificationItem* item);
   ~ArcCustomNotificationView() override;
 
   std::unique_ptr<message_center::CustomNotificationContentViewDelegate>
   CreateContentViewDelegate();
 
  private:
   class ContentViewDelegate;
   class EventForwarder;
@@ skipping 18 matching lines @@
   void CreateCloseButton();
   void CreateSettingsButton();
   void CreateFloatingControlButtons();
   void SetSurface(exo::NotificationSurface* surface);
   void UpdatePreferredSize();
   void UpdateControlButtonsVisibility();
   void UpdatePinnedState();
   void UpdateSnapshot();
   void AttachSurface();
   void ActivateToast();
+  void StartControlButtonsColorAnimation();
+  bool ShouldUpdateControlButtonsColor() const;
 
   // views::NativeViewHost
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;
   void Layout() override;
   void OnPaint(gfx::Canvas* canvas) override;
   void OnKeyEvent(ui::KeyEvent* event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
   void OnMouseEntered(const ui::MouseEvent& event) override;
   void OnMouseExited(const ui::MouseEvent& event) override;
@@ skipping 12 matching lines @@
   void OnWindowDestroying(aura::Window* window) override;
 
   // ArcCustomNotificationItem::Observer
   void OnItemDestroying() override;
   void OnItemUpdated() override;
 
   // ArcNotificationSurfaceManager::Observer:
   void OnNotificationSurfaceAdded(exo::NotificationSurface* surface) override;
   void OnNotificationSurfaceRemoved(exo::NotificationSurface* surface) override;
 
+  // AnimationDelegate
+  void AnimationEnded(const gfx::Animation* animation) override;
+  void AnimationProgressed(const gfx::Animation* animation) override;
+
   ArcCustomNotificationItem* item_ = nullptr;
   exo::NotificationSurface* surface_ = nullptr;
 
   const std::string notification_key_;
 
   // A pre-target event handler to forward events on the surface to this view.
   // Using a pre-target event handler instead of a target handler on the surface
   // window because it has descendant aura::Window and the events on them need
   // to be handled as well.
   // TODO(xiyuan): Revisit after exo::Surface no longer has an aura::Window.
   std::unique_ptr<EventForwarder> event_forwarder_;
 
   // A helper to observe slide transform/animation and use surface layer copy
   // when a slide is in progress and restore the surface when it finishes.
   std::unique_ptr<SlideHelper> slide_helper_;
 
   // A control buttons on top of NotificationSurface. Needed because the
   // aura::Window of NotificationSurface is added after hosting widget's
   // RootView thus standard notification control buttons are always below
   // it.
   std::unique_ptr<views::Widget> floating_control_buttons_widget_;
 
   views::View* control_buttons_view_ = nullptr;
   std::unique_ptr<ControlButton> close_button_;
   ControlButton* settings_button_ = nullptr;
 
   // Protects from call loops between Layout and OnWindowBoundsChanged.
   bool in_layout_ = false;
 
+  std::unique_ptr<gfx::LinearAnimation> control_button_color_animation_;
+
   DISALLOW_COPY_AND_ASSIGN(ArcCustomNotificationView);
 };
 
 }  // namespace arc
 
 #endif  // UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_VIEW_H_