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/Android.bp b/services/surfaceflinger/Android.bp
index 67a226e..c9c0143 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -155,6 +155,7 @@
         "DisplayRenderArea.cpp",
         "Effects/Daltonizer.cpp",
         "EventLog/EventLog.cpp",
+        "FrontEnd/TransactionHandler.cpp",
         "FlagManager.cpp",
         "FpsReporter.cpp",
         "FrameTracer/FrameTracer.cpp",
@@ -193,7 +194,6 @@
         "Tracing/TransactionTracing.cpp",
         "Tracing/TransactionProtoParser.cpp",
         "TransactionCallbackInvoker.cpp",
-        "TransactionHandler.cpp",
         "TunnelModeEnabledReporter.cpp",
     ],
 }