Remove the extra separator appears beside overview tray

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 513635d4b547fb55deab63b87cdcef47bb8cd229..7986b14b1d08a3556e750579ae9a65a2410ae8b6 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -222,8 +222,9 @@ SystemTray::SystemTray(WmShelf* wm_shelf)
     SetInkDropMode(InkDropMode::ON);
     SetContentsBackground(false);
 
-    // Since |system_tray| locates on the right most position, no separator is
-    // required on its right side.
+    // Since user avatar is on the right hand side of System tray of a
+    // horizontal shelf and that is sufficient to indicate separation, no
+    // separator is required.
     set_separator_visibility(false);
   } else {
     SetContentsBackground(true);