Add more fine-grained testing for Transactions

Bug: 129130064
Test: build, boot, libsurfaceflinger_unittest
Change-Id: I44b59c8b8c117353ee1da224cf4fe2c4290f0ec6
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index b9e95a6..54e2065 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -258,7 +258,8 @@
         mFrameTracer(std::make_unique<FrameTracer>()),
         mEventQueue(mFactory.createMessageQueue()),
         mCompositionEngine(mFactory.createCompositionEngine()),
-        mPhaseOffsets(mFactory.createPhaseOffsets()) {}
+        mPhaseOffsets(mFactory.createPhaseOffsets()),
+        mPendingSyncInputWindows(false) {}
 
 SurfaceFlinger::SurfaceFlinger(Factory& factory) : SurfaceFlinger(factory, SkipInitialization) {
     ALOGI("SurfaceFlinger is starting");