Remove ash tray utility functions that are no-ops in MD.

ash/common/system/tray/tray_image_item.cc

Index: ash/common/system/tray/tray_image_item.cc
diff --git a/ash/common/system/tray/tray_image_item.cc b/ash/common/system/tray/tray_image_item.cc
index da63db59b6e9e2b59756ba136ab20409e50e50fe..5c366ac8d7c2d8fec221510a2d94e9d521f3c770 100644
--- a/ash/common/system/tray/tray_image_item.cc
+++ b/ash/common/system/tray/tray_image_item.cc
@@ -40,28 +40,10 @@ views::View* TrayImageItem::CreateTrayView(LoginStatus status) {
   return tray_view_;
 }
 
-views::View* TrayImageItem::CreateDefaultView(LoginStatus status) {
-  return nullptr;
-}
-
-views::View* TrayImageItem::CreateDetailedView(LoginStatus status) {
-  return nullptr;
-}
-
-void TrayImageItem::UpdateAfterLoginStatusChange(LoginStatus status) {}
-
-void TrayImageItem::UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) {
-  SetTrayImageItemBorder(tray_view_, alignment);
-}
-
 void TrayImageItem::DestroyTrayView() {
   tray_view_ = nullptr;
 }
 
-void TrayImageItem::DestroyDefaultView() {}
-
-void TrayImageItem::DestroyDetailedView() {}
-
 void TrayImageItem::SetIconColor(SkColor color) {
   icon_color_ = color;
   UpdateImageOnImageView();