am ee874caa: Merge "DispSync: remove delay when enabling vsync events" into klp-dev

        EventListener listener;

        listener.mPhase = phase;

        listener.mCallback = callback;

        listener.mLastEventTime = systemTime(SYSTEM_TIME_MONOTONIC);

        // We want to allow the firstmost future event to fire without

        // allowing any past events to fire.  Because

        // computeListenerNextEventTimeLocked filters out events within a half

        // a period of the last event time, we need to initialize the last

        // event time to a half a period in the past.

        listener.mLastEventTime = systemTime(SYSTEM_TIME_MONOTONIC) - mPeriod / 2;

        mEventListeners.push(listener);

        mCond.signal();