Merge changes I6c0b77f4,I598a71b4 into tm-qpr-dev am: f03c3a83

  auto closure_started_future = closure_started.get_future();

  std::promise<void> closure_can_continue;

  auto can_continue_future = closure_can_continue.get_future();

  std::promise<void> closure_finished;

  auto closure_finished_future = closure_finished.get_future();

  handler_->Post(common::BindOnce(

      [](int* val, std::promise<void> closure_started, std::future<void> can_continue_future) {

      [](int* val,

         std::promise<void> closure_started,

         std::future<void> can_continue_future,

         std::promise<void> closure_finished) {

        closure_started.set_value();

        *val = *val + 1;

        can_continue_future.wait();

        closure_finished.set_value();

      },

      common::Unretained(&val),

      std::move(closure_started),

      std::move(can_continue_future)));

      std::move(can_continue_future),

      std::move(closure_finished)));

  handler_->Post(common::BindOnce([]() { ASSERT_TRUE(false); }));

  closure_started_future.wait();

  handler_->Clear();

  closure_can_continue.set_value();

  closure_finished_future.wait();

  ASSERT_EQ(val, 1);

}