Use pragma once (for simplicity).

Bug: N/A
Test: N/A
Change-Id: I7edde4a4593be5e12fe696d8ac71a35116c63b4b
diff --git a/ServiceManager.h b/ServiceManager.h
index e70110c..38bda57 100644
--- a/ServiceManager.h
+++ b/ServiceManager.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_HARDWARE_MANAGER_SERVICEMANAGER_H
-#define ANDROID_HARDWARE_MANAGER_SERVICEMANAGER_H
+#pragma once
 
 #include <android/hidl/manager/1.2/IServiceManager.h>
 #include <hidl/Status.h>
@@ -164,5 +163,3 @@
 }  // namespace manager
 }  // namespace hidl
 }  // namespace android
-
-#endif  // ANDROID_HARDWARE_MANAGER_SERVICEMANAGER_H