Simplify layout of tray items and fix spacing for MD.

ash/common/system/tray/tray_utils.cc

Index: ash/common/system/tray/tray_utils.cc
diff --git a/ash/common/system/tray/tray_utils.cc b/ash/common/system/tray/tray_utils.cc
index c427e654b3bdf2d90e360ccc1a0aca10461bb139..7828467496e2d45294aa05f4784619655129f03a 100644
--- a/ash/common/system/tray/tray_utils.cc
+++ b/ash/common/system/tray/tray_utils.cc
@@ -37,10 +37,10 @@ void SetupLabelForTray(views::Label* label) {
   }
 }
 
-// TODO(yiyix): Instead of using a fixed padding beside each tray item, take
-// internal icon padding into account when adjusting tray icon spacing. See
-// crbug.com/653292.
 void SetTrayImageItemBorder(views::View* tray_view, ShelfAlignment alignment) {
+  if (MaterialDesignController::IsShelfMaterial())

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

TrayItemView takes care of sizing, don't need this border as well

(yay compartmentalization)

[tdanderson, 2016/10/27 19:28:01]

Won't this still be needed by TrayPower::UpdateAfterShelfAlignmentChange()
(which isn't a TrayItemView)?

[Evan Stade, 2016/10/27 21:36:34]

yes. I saw that class, but figured it was working somehow because the
measurements between icons seemed correct. But that was because I was using
Sebastien's measurement from the visible edge of the wifi icon to the battery,
while comparing to the visible edge of a cell icon to the battery, which
magically compensated.

TrayPower should be a TrayItemView. Now it is.

+    return;
+
   const int tray_image_item_padding = GetTrayConstant(TRAY_IMAGE_ITEM_PADDING);
   if (IsHorizontalAlignment(alignment)) {
     tray_view->SetBorder(views::Border::CreateEmptyBorder(