Summary:
@public
`UIWebView` has been deprecated and replaced by `WKWebView`. This diff introduces a new component `WKWebView` that simply renders a `WKWebView` on iOS.
This is the first in the stack of many diffs that'll be required to fully replace `UIWebView` with `WKWebView` in the `<WebView/>` React Native component. Eventually, I hope to introduce a prop called `useWebKitImplementation`, which, when true, will force RN to use `WKWebView` instead of `UIWebView` for the `<WebView/>` component.
The only thing that's been implemented so far is the `source` property.
Reviewed By: mmmulani
Differential Revision: D6266100
fbshipit-source-id: 65862e34bd98db7fff0349cf26888afee43a56e4