Summary:
This adds new functionality to the `Image` component by allowing you to retrieve the width and height of an image just like you'd do with [`Image.getSize`](https://facebook.github.io/react-native/docs/image.html#getsize) but _with_ the ability to provide headers to your request.
Why would you need this you ask? Well, imagine that you have an image that you're loading into your `Image` component that is protected and you get access by using a token in a header (or something similar). That would work. However, getting the dimensions isn't possible since you can't provide those same headers.
This is something that is bothering me when using a third-party library (https://github.com/archriss/react-native-image-gallery) and instead of implementing this just for that single library I imagined that it would be useful for anyone else that needs to get the image dimensions before displaying it.
[Android] [Added] - Added Image.getSizeWithHeaders
[iOS] [Added] - Added Image.getSizeWithHeaders
Pull Request resolved: https://github.com/facebook/react-native/pull/18850
Differential Revision: D14434599
Pulled By: cpojer
fbshipit-source-id: 56d5e58889ddf7ddc12d5f6f7d9dc6921fa17884
c991e1c4cc