Simplify layout of tray items and fix spacing for 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 776b38f1ce7688881741cc4f6e14bfad92f71a6f..471a5acd7f4ffd6af9343bd05760edab372a4c95 100644
--- a/ash/common/system/tray/tray_image_item.cc
+++ b/ash/common/system/tray/tray_image_item.cc
@@ -89,7 +89,6 @@ void TrayImageItem::UpdateAfterLoginStatusChange(LoginStatus status) {}
 
 void TrayImageItem::UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) {
   SetTrayImageItemBorder(tray_view_, alignment);
-  SetItemAlignment(alignment);
 }
 
 void TrayImageItem::DestroyTrayView() {
@@ -110,15 +109,6 @@ void TrayImageItem::SetImageFromResourceId(int resource_id) {
   UpdateImageOnImageView();
 }
 
-void TrayImageItem::SetItemAlignment(ShelfAlignment alignment) {
-  // Center the item dependent on the orientation of the shelf.
-  views::BoxLayout::Orientation layout = IsHorizontalAlignment(alignment)
-                                             ? views::BoxLayout::kHorizontal

[Evan Stade, 2016/10/27 19:05:30]

use the TrayItemView's fill layout. ImageView already centers the actual Image.

[tdanderson, 2016/10/27 19:28:00]

Acknowledged.

-                                             : views::BoxLayout::kVertical;
-  tray_view_->SetLayoutManager(new views::BoxLayout(layout, 0, 0, 0));
-  tray_view_->Layout();
-}
-
 void TrayImageItem::UpdateImageOnImageView() {
   if (!tray_view_)
     return;