Remove MessageLoop references in services/device/battery

MessageLoop is going away soon.

This CL was uploaded by git cl split.

R=timvolodine@chromium.org

Bug: 891670
Change-Id: I3fb93bf9474d1d021bb8d023166d0301429d6240
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1878073Reviewed-by: Tim Volodine <timvolodine@chromium.org>
Commit-Queue: Carlos Caballero <carlscab@google.com>
Auto-Submit: Carlos Caballero <carlscab@google.com>
Cr-Commit-Position: refs/heads/master@{#709489}

services/device/battery/battery_status_service_unittest.cc

@@ -9,8 +9,8 @@
 
 #include "base/bind.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/test/task_environment.h"
 #include "services/device/battery/battery_status_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -110,7 +110,7 @@ class BatteryStatusServiceTest : public testing::Test {
     battery_status_ = status;
   }
 
-  base::MessageLoop message_loop_;
+  base::test::SingleThreadTaskEnvironment task_environment_;
   BatteryStatusService battery_service_;
   FakeBatteryManager* battery_manager_;
   BatteryStatusService::BatteryUpdateCallback callback1_;