Adding onTransact method for testing

Test: Tested locally for fuzzing
Change-Id: Ieadc20860e1f235b8f7cb6eda40c74d286b3d86b
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 38bc8a1..cbf264d 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -365,6 +365,10 @@
 
     auto flushTransactionQueues() { return mFlinger->flushTransactionQueues(); };
 
+    auto onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags) {
+        return mFlinger->onTransact(code, data, reply, flags);
+    }
+
     /* ------------------------------------------------------------------------
      * Read-only access to private data to assert post-conditions.
      */