Add trunk flag for adding SF skipped frames into traces.

Bug: 273701290
Test: FrameTimelineTest#traceDisplayFrameSkipped, play with perfetto
Change-Id: Ib5f884a14dc6526e2a2b5a1371be7715a20cd0a9
diff --git a/services/surfaceflinger/common/FlagManager.cpp b/services/surfaceflinger/common/FlagManager.cpp
index 8da7d8e..e2a1498 100644
--- a/services/surfaceflinger/common/FlagManager.cpp
+++ b/services/surfaceflinger/common/FlagManager.cpp
@@ -120,6 +120,7 @@
     DUMP_READ_ONLY_FLAG(hotplug2);
     DUMP_READ_ONLY_FLAG(hdcp_level_hal);
     DUMP_READ_ONLY_FLAG(multithreaded_present);
+    DUMP_READ_ONLY_FLAG(add_sf_skipped_frames_to_trace);
 
 #undef DUMP_READ_ONLY_FLAG
 #undef DUMP_SERVER_FLAG
@@ -188,6 +189,7 @@
 FLAG_MANAGER_READ_ONLY_FLAG(hotplug2, "")
 FLAG_MANAGER_READ_ONLY_FLAG(hdcp_level_hal, "")
 FLAG_MANAGER_READ_ONLY_FLAG(multithreaded_present, "debug.sf.multithreaded_present")
+FLAG_MANAGER_READ_ONLY_FLAG(add_sf_skipped_frames_to_trace, "")
 
 /// Trunk stable server flags ///
 FLAG_MANAGER_SERVER_FLAG(late_boot_misc2, "")