Make spacing between uber tray items consistent with UI spec.

ash/system/tray/tray_item_view.h

Index: ash/system/tray/tray_item_view.h
diff --git a/ash/system/tray/tray_item_view.h b/ash/system/tray/tray_item_view.h
index f5fa8afdbb1551b8b7f52bb55a6740981c29b697..f839cc8aeb1b6047249063c1efb0854674d115fd 100644
--- a/ash/system/tray/tray_item_view.h
+++ b/ash/system/tray/tray_item_view.h
@@ -29,7 +29,7 @@ class TrayItemView : public views::View,
   TrayItemView();
   virtual ~TrayItemView();
 
-  // Conveniece function for creating a child Label or ImageView.
+  // Convenience function for creating a child Label or ImageView.
   void CreateLabel();
   void CreateImageView();
 
@@ -38,6 +38,7 @@ class TrayItemView : public views::View,
 
   // Overridden from views::View.
   virtual void SetVisible(bool visible) OVERRIDE;
+  virtual gfx::Size GetPreferredSize() OVERRIDE;
 
  protected:
   // Makes sure the widget relayouts after the size/visibility of the view
@@ -55,7 +56,6 @@ class TrayItemView : public views::View,
 
  private:
   // Overridden from views::View.
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual void ChildPreferredSizeChanged(View* child) OVERRIDE;
 
   // Overridden from ui::AnimationDelegate.