fix a small race condition when returning the default width/height of a SurfaceTexture

        mSlots[buf].mScalingMode = mNextScalingMode;

        mSlots[buf].mTimestamp = timestamp;

        mDequeueCondition.signal();

        *outWidth = mDefaultWidth;

        *outHeight = mDefaultHeight;

        *outTransform = 0;

    } // scope for the lock

    // call back without lock held

    if (listener != 0) {

        listener->onFrameAvailable();

    }

    *outWidth = mDefaultWidth;

    *outHeight = mDefaultHeight;

    *outTransform = 0;

    return OK;

}