MD system tray: Add user metrics for clicks on the Bluetooth toggle switch.

ash/common/system/chromeos/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/common/system/chromeos/bluetooth/tray_bluetooth.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/system/tray/fixed_sized_scroll_view.h"
 #include "ash/common/system/tray/hover_highlight_view.h"
@@ skipping 519 matching lines @@
     const std::string device_id = find->second;
     if (FoundDevice(device_id, connecting_devices_, nullptr, nullptr))
       return;
 
     UpdateClickedDevice(device_id, view);
     delegate->ConnectToBluetoothDevice(device_id);
   }
 
   void HandleButtonPressed(views::Button* sender,
                            const ui::Event& event) override {
+    SystemTrayDelegate* delegate = WmShell::Get()->system_tray_delegate();
     if (UseMd()) {
-      if (sender == toggle_)
-        WmShell::Get()->system_tray_delegate()->ToggleBluetooth();
-      else if (sender == settings_)
+      if (sender == toggle_) {
+        WmShell::Get()->RecordUserMetricsAction(
+            delegate->GetBluetoothEnabled()
+                ? UMA_STATUS_AREA_BLUETOOTH_DISABLED
+                : UMA_STATUS_AREA_BLUETOOTH_ENABLED);
+        delegate->ToggleBluetooth();
+      } else if (sender == settings_) {
         ShowSettings();
-      else
+      } else {
         NOTREACHED();
+      }
       return;
     }
 
-    SystemTrayDelegate* delegate = WmShell::Get()->system_tray_delegate();
     if (sender == toggle_bluetooth_)
       delegate->ToggleBluetooth();
     else
       NOTREACHED();
   }
 
   void CreateExtraTitleRowButtons() override {
     if (login_ == LoginStatus::LOCKED)
       return;
 
@@ skipping 202 matching lines @@
     detailed_->Update();
 }
 
 void TrayBluetooth::OnBluetoothDiscoveringChanged() {
   if (!detailed_)
     return;
   detailed_->Update();
 }
 
 }  // namespace ash