SF: Do not trace FrameTimeline before start

Filter FrameTimeline events for frames started before the trace started.

Bug: 364194637
Test: manual
Flag: com.android.graphics.surfaceflinger.flags.filter_frames_before_trace_starts
Change-Id: I9185f384f306eddab1afc2ea9d7901dd70d2f1a2
diff --git a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
index 9be0fc3..0dfbd61 100644
--- a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
+++ b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
@@ -84,9 +84,11 @@
 
     void SetUp() override {
         constexpr bool kUseBootTimeClock = true;
+        constexpr bool kFilterFramesBeforeTraceStarts = false;
         mTimeStats = std::make_shared<mock::TimeStats>();
         mFrameTimeline = std::make_unique<impl::FrameTimeline>(mTimeStats, kSurfaceFlingerPid,
-                                                               kTestThresholds, !kUseBootTimeClock);
+                                                               kTestThresholds, !kUseBootTimeClock,
+                                                               kFilterFramesBeforeTraceStarts);
         mFrameTimeline->registerDataSource();
         mTokenManager = &mFrameTimeline->mTokenManager;
         mTraceCookieCounter = &mFrameTimeline->mTraceCookieCounter;