cros: Remove some OS platform ifdefs from ash

ash/metrics/user_metrics_recorder.h

Index: ash/metrics/user_metrics_recorder.h
diff --git a/ash/metrics/user_metrics_recorder.h b/ash/metrics/user_metrics_recorder.h
index e2aca6699597b83cc76c411fd8ff70ee480f72f6..7437dff31c32a8e399c02948e7b71d664855ed1c 100644
--- a/ash/metrics/user_metrics_recorder.h
+++ b/ash/metrics/user_metrics_recorder.h
@@ -16,10 +16,7 @@
 namespace ash {
 
 class DesktopTaskSwitchMetricRecorder;
-
-#if defined(OS_CHROMEOS)
 class PointerMetricsRecorder;
-#endif
 
 namespace test {
 class UserMetricsRecorderTestAPI;
@@ -82,10 +79,8 @@ class ASH_EXPORT UserMetricsRecorder {
   std::unique_ptr<DesktopTaskSwitchMetricRecorder>
       desktop_task_switch_metric_recorder_;
 
-#if defined(OS_CHROMEOS)
   // Metric recorder to track pointer down events.
   std::unique_ptr<PointerMetricsRecorder> pointer_metrics_recorder_;
-#endif
 
   DISALLOW_COPY_AND_ASSIGN(UserMetricsRecorder);
 };