Vsyncs are hard

            mPendingRegistrationFrameCallbacks.clear();

            requestVsync();

        }

        if (!mFrameCallbackTaskPending && !mVsyncRequested && mFrameCallbacks.size()) {

            // TODO: Clean this up. This is working around an issue where a combination

            // of bad timing and slow drawing can result in dropping a stale vsync

            // on the floor (correct!) but fails to schedule to listen for the

            // next vsync (oops), so none of the callbacks are run.

            requestVsync();

        }

    }

    return false;