SF: Move TransactionHandler to frontend

Makes it easier to carve out a library in
the future.

Test: presubmit
Bug: 238781169
Change-Id: Iaaa576b47b226114eba48606bffa9ed0dc77c71a
diff --git a/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp b/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
index db438b7..de84faa 100644
--- a/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
+++ b/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
@@ -30,8 +30,8 @@
 #include <vector>
 #include <binder/Binder.h>
 
+#include "FrontEnd/TransactionHandler.h"
 #include "TestableSurfaceFlinger.h"
-#include "TransactionHandler.h"
 #include "mock/MockEventThread.h"
 #include "mock/MockVsyncController.h"