Fix shelf layout when switching from left-aligned shelf to right-aligned shelf

ash/common/system/tray/tray_background_view.h

Index: ash/common/system/tray/tray_background_view.h
diff --git a/ash/common/system/tray/tray_background_view.h b/ash/common/system/tray/tray_background_view.h
index 478e427bda77e0b79719747d9decd52ee0a0e6a2..6dc6386f2e5238fb3d30aa54c6d191c6e30ee78a 100644
--- a/ash/common/system/tray/tray_background_view.h
+++ b/ash/common/system/tray/tray_background_view.h
@@ -15,6 +15,10 @@
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/views/bubble/tray_bubble_view.h"
 
+namespace gfx {
+class Insets;
+}
+
 namespace ash {
 class ShelfLayoutManager;
 class TrayEventFilter;
@@ -65,8 +69,9 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   explicit TrayBackgroundView(WmShelf* wm_shelf);
   ~TrayBackgroundView() override;
 
-  // Called after the tray has been added to the widget containing it.
-  virtual void Initialize();
+  // Called after the tray has been added to the widget containing it. Set the
+  // tray items with border specified in |insets|.
+  virtual void Initialize(const gfx::Insets& insets);
 
   // Initializes animations for the bubble.
   static void InitializeBubbleAnimations(views::Widget* bubble_widget);
@@ -86,8 +91,10 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // BackgroundAnimatorDelegate:
   void UpdateBackground(int alpha) override;
 
-  // Called whenever the shelf alignment changes.
-  virtual void SetShelfAlignment(ShelfAlignment alignment);
+  // Called whenever the shelf alignment changes and set the tray items with the
+  // new border based on alignment specified in |insets|.
+  virtual void SetShelfAlignment(ShelfAlignment alignment,
+                                 const gfx::Insets& insets);
 
   // Called when the anchor (tray or bubble) may have moved or changed.
   virtual void AnchorUpdated() {}
@@ -139,8 +146,8 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   class TrayWidgetObserver;
 
   // Called from Initialize after all status area trays have been created.
-  // Sets the border based on the position of the view.
-  void SetTrayBorder();
+  // Sets the border based on given |insets|.
+  void SetTrayBorder(const gfx::Insets& insets);
 
   // ui::ImplicitAnimationObserver:
   void OnImplicitAnimationsCompleted() override;