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/FrameTimeline/FrameTimeline.cpp b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
index dfbb55d..9dc3938 100644
--- a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
+++ b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
@@ -21,6 +21,7 @@
 #include "FrameTimeline.h"
 
 #include <android-base/stringprintf.h>
+#include <common/FlagManager.h>
 #include <utils/Log.h>
 #include <utils/Trace.h>
 
@@ -1200,7 +1201,9 @@
         surfaceFrame->trace(mToken, monoBootOffset);
     }
 
-    addSkippedFrame(surfaceFlingerPid, monoBootOffset, previousActualPresentTime);
+    if (FlagManager::getInstance().add_sf_skipped_frames_to_trace()) {
+        addSkippedFrame(surfaceFlingerPid, monoBootOffset, previousActualPresentTime);
+    }
 }
 
 float FrameTimeline::computeFps(const std::unordered_set<int32_t>& layerIds) {