Animating docked background in sync with shelf

ash/wm/dock/docked_window_layout_manager.h

Index: ash/wm/dock/docked_window_layout_manager.h
diff --git a/ash/wm/dock/docked_window_layout_manager.h b/ash/wm/dock/docked_window_layout_manager.h
index 9cb38265c75e8a1eb00c6412c93037591c4c8df7..8e6238ea0f610b6fbfe0efd2fe3f7e0df39d792f 100644
--- a/ash/wm/dock/docked_window_layout_manager.h
+++ b/ash/wm/dock/docked_window_layout_manager.h
@@ -41,6 +41,7 @@ namespace ash {
 class Launcher;
 
 namespace internal {
+class DockedBackgroundWidget;
 class DockedWindowLayoutManagerObserver;
 class DockedWindowResizerTest;
 class ShelfLayoutManager;
@@ -74,6 +75,7 @@ class ASH_EXPORT DockedWindowLayoutManager
       public aura::WindowObserver,
       public aura::client::ActivationChangeObserver,
       public keyboard::KeyboardControllerObserver,
+      public ShelfLayoutManagerObserver,
       public wm::WindowStateObserver {
  public:
   // Maximum width of the docked windows area.
@@ -148,6 +150,11 @@ class ASH_EXPORT DockedWindowLayoutManager
                                         aura::Window* root_window) OVERRIDE;
   virtual void OnShelfAlignmentChanged(aura::Window* root_window) OVERRIDE;
 
+  // ShelfLayoutManagerObserver:
+  virtual void OnBackgroundUpdated(
+      ShelfBackgroundType background_type,
+      BackgroundAnimatorChangeType change_type) OVERRIDE;
+
   // wm::WindowStateObserver:
   virtual void OnWindowShowTypeChanged(wm::WindowState* window_state,
                                        wm::WindowShowType old_type) OVERRIDE;
@@ -255,6 +262,7 @@ class ASH_EXPORT DockedWindowLayoutManager
 
   // The launcher to respond to launcher alignment changes.
   Launcher* launcher_;
+
   // Workspace controller that can be checked for fullscreen mode.
   WorkspaceController* workspace_controller_;
   // Tracks if any window in the same root window is in fullscreen mode.
@@ -280,7 +288,7 @@ class ASH_EXPORT DockedWindowLayoutManager
   base::Time last_action_time_;
 
   // Widget used to paint a background for the docked area.
-  scoped_ptr<views::Widget> background_widget_;
+  scoped_ptr<DockedBackgroundWidget> background_widget_;
 
   // Observers of dock bounds changes.
   ObserverList<DockedWindowLayoutManagerObserver> observer_list_;