Add a row in the network tray to inform users to turn Bluetooth on to enable Tether.

ash/system/bluetooth/tray_bluetooth.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/bluetooth/tray_bluetooth.h"
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/bluetooth/tray_bluetooth_helper.h"
 #include "ash/system/tray/hover_highlight_view.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_controller.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_details_view.h"
+#include "ash/system/tray/tray_info_label.h"
 #include "ash/system/tray/tray_item_more.h"
 #include "ash/system/tray/tray_popup_item_style.h"
 #include "ash/system/tray/tray_popup_utils.h"
 #include "ash/system/tray/tri_view.h"
 #include "device/bluetooth/bluetooth_common.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/color_palette.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/paint_vector_icon.h"
@@ skipping 274 matching lines @@
     // present, also add a section header above the unpaired devices.
     if (discovered_not_paired_devices_.size() > 0) {
       if (num_paired_devices > 0)
         AddScrollListSubHeader(IDS_ASH_STATUS_TRAY_BLUETOOTH_UNPAIRED_DEVICES);
       AppendSameTypeDevicesToScrollList(discovered_not_paired_devices_, false,
                                         false, bluetooth_enabled);
     }
 
     // Show user Bluetooth state if there is no bluetooth devices in list.
     if (device_map_.size() == 0 && bluetooth_available && bluetooth_enabled) {
-      scroll_content()->AddChildView(
-          new InfoLabel(IDS_ASH_STATUS_TRAY_BLUETOOTH_DISCOVERING));
+      scroll_content()->AddChildView(new TrayInfoLabel(
+          nullptr /* delegate */, IDS_ASH_STATUS_TRAY_BLUETOOTH_DISCOVERING));
     }
 
     // Focus the device which was focused before the device-list update.
     if (!focused_device_address.empty())
       FocusDeviceByAddress(focused_device_address);
 
     scroll_content()->InvalidateLayout();
   }
 
   void AppendSameTypeDevicesToScrollList(const BluetoothDeviceList& list,
@@ skipping 241 matching lines @@
     detailed_->Update();
 }
 
 void TrayBluetooth::OnBluetoothDiscoveringChanged() {
   if (!detailed_)
     return;
   detailed_->Update();
 }
 
 }  // namespace ash