[Power] fix OnScreenStateChanged error

Change-Id: Ie9df2411fd5ddab1be83930e6a27687e5b5533ed

diff --git a/src/power/power_manager.h b/src/power/power_manager.h
index ce98cf90354f5912f0f58105270acde6196c1b3f..a96e02963e4e37d06f6298aeb652502d0017f709 100755 (executable)
--- a/src/power/power_manager.h
+++ b/src/power/power_manager.h
@@ -28,7 +28,7 @@ enum PowerState {
 
 class PowerManagerListener {
  public:
-  void OnScreenStateChanged(PowerState prev_state, PowerState new_state);
+  virtual void OnScreenStateChanged(PowerState prev_state, PowerState new_state)=0;
 };
 
 class PowerManager {