Reland: Add test for system tray network menu icon for extension-controlled networks

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 cb725a9d4b6603c4ed781c986ee97dd0e596ddcb..bf77079841f884a8a62c18b7cdb6fb077657de4d 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -216,6 +216,7 @@ SystemTray::SystemTray(WmShelf* wm_shelf)
       tray_audio_(nullptr),
       tray_cast_(nullptr),
       tray_date_(nullptr),
+      tray_network_(nullptr),
       tray_tiles_(nullptr),
       tray_system_info_(nullptr),
       tray_update_(nullptr),
@@ -290,7 +291,8 @@ void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   AddTrayItem(tray_accessibility_);
   AddTrayItem(new TrayTracing(this));
   AddTrayItem(new TrayPower(this, message_center::MessageCenter::Get()));
-  AddTrayItem(new TrayNetwork(this));
+  tray_network_ = new TrayNetwork(this);
+  AddTrayItem(tray_network_);
   AddTrayItem(new TrayVPN(this));
   AddTrayItem(new TraySms(this));
   AddTrayItem(new TrayBluetooth(this));
@@ -808,6 +810,10 @@ TrayDate* SystemTray::GetTrayDateForTesting() const {
   return tray_date_;
 }
 
+TrayNetwork* SystemTray::GetTrayNetworkForTesting() const {
+  return tray_network_;
+}
+
 TraySystemInfo* SystemTray::GetTraySystemInfoForTesting() const {
   return tray_system_info_;
 }