Return sp on call to createSurfaceInterceptor

This is so that SurfaceInterceptor can implement IBinder::DeathRecipient, since that inherits RefBase.h and must be stored as an sp.

Test: Make sure the device boot when SurfaceInterceptor extends RefBase
Change-Id: I264cd9e0a8517ae5a425b3a493631c7c42220473
diff --git a/services/surfaceflinger/SurfaceFlingerFactory.h b/services/surfaceflinger/SurfaceFlingerFactory.h
index 753476e..41ccc10 100644
--- a/services/surfaceflinger/SurfaceFlingerFactory.h
+++ b/services/surfaceflinger/SurfaceFlingerFactory.h
@@ -73,7 +73,7 @@
             const scheduler::RefreshRateConfigs&) = 0;
     virtual std::unique_ptr<Scheduler> createScheduler(const scheduler::RefreshRateConfigs&,
                                                        ISchedulerCallback&) = 0;
-    virtual std::unique_ptr<SurfaceInterceptor> createSurfaceInterceptor(SurfaceFlinger*) = 0;
+    virtual sp<SurfaceInterceptor> createSurfaceInterceptor(SurfaceFlinger*) = 0;
 
     virtual sp<StartPropertySetThread> createStartPropertySetThread(
             bool timestampPropertyValue) = 0;