camera进入后台被关闭问题

由于谷歌策略机制，camera无法在后台长时间运行，activity在判断camera进入后台后，会调用到

frameworks/av/services/camera/libcameraservice/common

template 
binder::Status Camera2ClientBase::disconnect() {
    ATRACE_CALL();
    Mutex::Autolock icl(mBinderSerializationLock);

    binder::Status res = binder::Status::ok();
    // Allow both client and the media server to disconnect at all times
    int callingPid = getCallingPid();
    if (callingPid != TClientBase::mClientPid &&
        callingPid != TClientBase::mServicePid) return res;

    ALOGV("Camera %s: Shutting down", TClientBase::mCameraIdStr.string());

    detachDevice();

    CameraService::BasicClient::disconnect();

    ALOGV("Camera %s: Shut down complete complete", TClientBase::mCameraIdStr.string());

    return res;
}

可以在这里修改，判断pid等于0，则直接返回。

但是正规方法还是应该在blockClientsForUid除判断包名来进行屏蔽