Migrate simple ash Shell metrics users.

ash/system/chromeos/keyboard_brightness_controller.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/chromeos/keyboard_brightness_controller.h"
 
-#include "ash/metrics/user_metrics_recorder.h"
-#include "ash/shell.h"
+#include "ash/common/wm_shell.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "ui/base/accelerators/accelerator.h"
 
 namespace ash {
 
 void KeyboardBrightnessController::HandleKeyboardBrightnessDown(
     const ui::Accelerator& accelerator) {
   if (accelerator.key_code() == ui::VKEY_BRIGHTNESS_DOWN) {
-    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
+    WmShell::Get()->RecordUserMetricsAction(
         UMA_ACCEL_KEYBOARD_BRIGHTNESS_DOWN_F6);
   }
 
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       DecreaseKeyboardBrightness();
 }
 
 void KeyboardBrightnessController::HandleKeyboardBrightnessUp(
     const ui::Accelerator& accelerator) {
   if (accelerator.key_code() == ui::VKEY_BRIGHTNESS_UP) {
-    Shell::GetInstance()->metrics()->RecordUserMetricsAction(
+    WmShell::Get()->RecordUserMetricsAction(
         UMA_ACCEL_KEYBOARD_BRIGHTNESS_UP_F7);
   }
 
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       IncreaseKeyboardBrightness();
 }
 
 }  // namespace ash