Migrate simple ash Shell metrics users.

ash/system/chromeos/keyboard_brightness_controller.cc

Index: ash/system/chromeos/keyboard_brightness_controller.cc
diff --git a/ash/system/chromeos/keyboard_brightness_controller.cc b/ash/system/chromeos/keyboard_brightness_controller.cc
index 59e438a77a1614ed9211985116697972042be1f9..8b8c3fbbfb43f7afad7b0a9ffb67aec34a07403d 100644
--- a/ash/system/chromeos/keyboard_brightness_controller.cc
+++ b/ash/system/chromeos/keyboard_brightness_controller.cc
@@ -4,8 +4,7 @@
 
 #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"
@@ -15,7 +14,7 @@ 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);
   }
 
@@ -26,7 +25,7 @@ void KeyboardBrightnessController::HandleKeyboardBrightnessDown(
 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);
   }