RN下支持camera

[wangxiaokou]

1. api-proxy补充createCameraContext
2. core中增加同一个页面引入多个camera异常
3. webpack-plugin中增加camera组件

[hiyuki]

包裹个useMemo只需要创建一次

[hiyuki]

camera = useMemo(()=>{
return {...}
}, [])

useEffect(()=>{
return ()=>{
if(navigation.camera === camera){
delete navigation.camera
}
}
}, [])

if(navigation.camera && navigation.camera !== camera ) {
warn()
return null
} else {
navigation.camera = camera
}

return createElement(Camera)

[dos1in]

需要传递 torch 属性给相机组件：torch: flash === 'on' ? 'on' : flash === 'off' ? 'off' : undefined