camera: add traces for KPI measurement

Bug: 17658101
Change-Id: I1d8035c4a8fba7b88a87f205ce57c13d812e9df5
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.h b/services/camera/libcameraservice/device3/Camera3OutputStream.h
index f963326..be278c5 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.h
@@ -84,6 +84,8 @@
 
     virtual status_t  setTransformLocked(int transform);
 
+    bool mTraceFirstBuffer;
+
     /**
      * Internal Camera3Stream interface
      */