[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/tray/system_tray.cc

Index: ash/common/system/tray/system_tray.cc
diff --git a/ash/common/system/tray/system_tray.cc b/ash/common/system/tray/system_tray.cc
index 75a6b093c7e8bcad0b1bfa15c65578d7ce865ab2..143d0499cbe3b036b2702723e2ea0e744bec9092 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -6,6 +6,7 @@
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/login_status.h"
+#include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shelf/wm_shelf_util.h"
@@ -73,6 +74,9 @@ namespace ash {
 // The minimum width of the system tray menu width.
 const int kMinimumSystemTrayMenuWidth = 300;
 
+// Padding used to adjust the user-visible size of status tray dark background.
+const int kBackgroundTrayPadding = 3;
+
 // Class to initialize and manage the SystemTrayBubble and TrayBubbleWrapper
 // instances for a bubble.
 
@@ -155,6 +159,7 @@ void SystemTray::InitializeTrayItems(
   DCHECK(web_notification_tray);
   web_notification_tray_ = web_notification_tray;
   TrayBackgroundView::Initialize();
+  AdjustStatusTrayBackground();
   CreateItems(delegate);
 }
 
@@ -627,6 +632,9 @@ void SystemTray::SetShelfAlignment(ShelfAlignment alignment) {
   if (alignment == shelf_alignment())
     return;
   TrayBackgroundView::SetShelfAlignment(alignment);
+  if (!ash::MaterialDesignController::IsShelfMaterial())
+    AdjustStatusTrayBackground();
+
   UpdateAfterShelfAlignmentChange(alignment);
   // Destroy any existing bubble so that it is rebuilt correctly.
   CloseSystemBubbleAndDeactivateSystemTray();
@@ -794,4 +802,11 @@ void SystemTray::RecordSystemMenuMetrics() {
   }
 }
 
+void SystemTray::AdjustStatusTrayBackground() {
+  if (!ash::MaterialDesignController::IsShelfMaterial()) {
+    tray_container()->SetBorder(
+        views::Border::CreateEmptyBorder(gfx::Insets(kBackgroundTrayPadding)));
+  }
+}
+
 }  // namespace ash