camera進入後臺被關閉問題

由於谷歌策略機制，camera無法在後臺長時間運行，activity在判斷camera進入後臺後，會調用到

frameworks/av/services/camera/libcameraservice/common

template <typename TClientBase>
binder::Status Camera2ClientBase<TClientBase>::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;
}

可以在這裏修改，判斷pid等於0，則直接返回。

但是正規方法還是應該在blockClientsForUid除判斷包名來進行屏蔽