Summary:
public
https://github.com/facebook/react-native/pull/5494 added a new `source` property to WebView on Android that provides a better API, as well as allowing for request headers to be set.
This diff ports that functionality over to iOS, so we can have a consistent API cross-platform.
I've also extended the API to include `method` (GET or POST) and `body` when setting the WebView content with a URI, and `baseUrl` when setting static HTML.
Reviewed By: javache
Differential Revision: D2884643
fb-gh-sync-id: 83f24494bdbb4e1408aa8f3b7428fee33888ae3a
46106f756a