MediaSyncEvent: Fix thread safety

Test: atest synchronizedrecordstate_tests
Test: atest MediaSyncEventTest#testSynchronizedRecord
Bug: 281168109
Change-Id: I75677947ab2b508d20d55256187830c3ace9c9e9
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 6b50693..a470478 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -90,6 +90,7 @@
 #include <sounddose/SoundDoseManager.h>
 #include <timing/MonotonicFrameCounter.h>
 #include <timing/SyncEvent.h>
+#include <timing/SynchronizedRecordState.h>
 
 #include "FastCapture.h"
 #include "FastMixer.h"