There must be equal number of start/end calls with right token given in order, if used in wrong order, ProtoOutputStream will have empty output. Also refactor Android.bp, so the gtest is standalone unit test, it used to require compile/push libprotoutil.so to device. Bug: 77342154 Test: atest libprotoutil_test Change-Id: I0011bbab34c04cb38164d2ed21cd818d52a2ecf9