`onFileDownload` is called with the URL that you can use to download the file.
When RNCWebView detects that the HTTP response should result in a file download,
`onFileDownload` is called. The client can then provide code to download
the file.

RNCWebView determines that a file download should take place if either of the
following is true:
1. The HTTP response contains a `Content-Disposition` header that is of type
  'attachment'
2. The MIME type of the response cannot be rendered by the iOS WebView

This converter is already defined in
[RCTScrollViewManager.m](https://github.com/facebook/react-native/blob/master/React/Views/ScrollView/RCTScrollViewManager.m#L40).

Redefining it in react-native-webview can cause undefined behaviour when
used. Since ScrollView is unlikely to go away, we can take a dependency on it.

All current tests should pass.

When building a React Native app with `react-native-webview`, the following
warning can be seen in the build logs:

```
Meta method 'UIScrollViewContentInsetAdjustmentBehavior:' in category from /~/Library/Developer/Xcode/DerivedData/App-geojljebaazfrrgvxfkjjpiwmdlg/Build/Products/Debug-iphonesimulator/React-Core/libReact-Core.a(RCTScrollViewManager.o) conflicts with same method from another category
```

The warning should go away after removing the offending function.

Co-authored-by: Jason Safaiyeh <safaiyeh@protonmail.com>

* Run the injectedJavaScript on DocumentStart for iOS

* Add new prop injectedJavaScriptBeforeContentLoaded
Update types
Update docs

* Self review

* Add callback for WKWebView's onContentProcessDidTerminate

* Add platform information to docs

* Add new WebViewTerminatedEvent type

Apple required us to remove this (see #819)

BREAKING CHANGE: UIWebView has been removed
BREAKING CHANGE: useWebkit prop removal
BREAKING CHANGE: scalesPageToFit prop removal on iOS (since it's not compatible with WKWebview)
BREAKING CHANGE: Renamed RNCWKWebView to RNCWebView on iOS

* Adding a `contentInsetAdjustmentBehavior` prop to the WebView for iOS.
This controls the way iOS will automatically adjust the insets when the
webview is behind things like the iPhone X notch.

* Removing the code to explicitly pass contentInsetAdjustmentBehavior to the WebView since it is already passed in otherProps.

* Add `onScroll` callback for iOS & Android

This code was mostly extracted from https://github.com/react-native-community/react-native-webview/pull/202

I tried and tried to make it work with `Animated.event`'s `useNativeDriver`, but I was unsuccessful 😢 that'll have to be done later once I understand better how Animated's native stuff is hooked up.

* fix crash for missing onScroll

* [iOS] Allow focus without user interaction

* Add documentation for keyboardDisplayRequiresUserAction

* set keyboardDisplayRequiresUserAction default to true

We had the problem on iOS WebViews that local cookies (stored in local HTTPCookieStorage, set with  [react-native-cookie](https://github.com/shimohq/react-native-cookie) ) were not added in loadRequests. On Android the local stored cookies were sent like expected.
This kinda "hacky" solution is the only way we found, that works for us.
The stack overview link is in the code below.
If someone finds a better solution we would very much like to accept that.

Added a new cacheEnabled prop to toggle Android & iOS webview caching behavior.

BREAKING CHANGE:  This change makes caching enabled by default when previously there was no caching behavior which may cause unexpected behaviour changes in your existing implementations.

Allows the webview to be opened with an ephemeral data storage.

* fix(WKWebview): [iOS] Add shared process pool so cookies and localStorage are shared across webviews (#68)

* Add optional shared process pool

BREAKING CHANGE: useSharedProcessPool prop is set to true by default. If you want the old behavior, please use useSharedProcessPool={false}

* [ios] Add ‘allowsLinkPreview’ property to iOS WKWebView.

* Add divider in docs

* Typo: add hyphen -> _allowsLinkPreview

* Add 'userAgent' property to the iOS WKWebView

* Update 'userAgent' reference docs.

* add hideKeyboardAccessoryView option

* add hideKeyboardAccessoryView prop to reference

* Added the onLoadProgress property to the iOS wkwebview and Android webview