Make spacing between uber tray items consistent with UI spec.

ash/system/tray/tray_views.h

Index: ash/system/tray/tray_views.h
diff --git a/ash/system/tray/tray_views.h b/ash/system/tray/tray_views.h
index e1e612d0614a2ba0b7f8564f2c7ae29391ff0bb8..7f8cef03e54bed6d45c689f3b3721f55159d377c 100644
--- a/ash/system/tray/tray_views.h
+++ b/ash/system/tray/tray_views.h
@@ -6,6 +6,7 @@
 #define ASH_SYSTEM_TRAY_TRAY_VIEWS_H_
 
 #include "ash/ash_export.h"
+#include "ash/wm/shelf_types.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/size.h"
 #include "ui/views/controls/button/image_button.h"
@@ -29,6 +30,8 @@ class BoxLayout;
 namespace ash {
 namespace internal {
 
+class TrayItemView;
+
 // An image view with a specified width and height (kTrayPopupDetailsIconWidth).
 // If the specified width or height is zero, then the image size is used for
 // that dimension.
@@ -255,6 +258,15 @@ class SpecialPopupRow : public views::View {
 // Sets up a Label properly for the tray (sets color, font etc.).
 void SetupLabelForTray(views::Label* label);
 
+// TODO(jennyz): refactor these two functions to SystemTrayItem.
+// Sets the empty border of an image tray item for adjusting the space
+// around it.
+void SetTrayImageItemBorder(views::View* tray_view, ShelfAlignment alignment);
+// Sets the empty border around a label tray item for adjusting the space
+// around it.
+void SetTrayLabelItemBorder(TrayItemView* tray_view,
+                            ShelfAlignment alignment);
+
 }  // namespace internal
 }  // namespace ash