Hedger Wang 54825b304a [WebView]: Kill shouldInjectAJAXHandler, and add injectedJavascriptIOS ...

Summary:
@public

The API and implementation of `shouldInjectAJAXHandler` is very opinionated, and it does not solve many of the use cases that we'd like to address.

Since  `shouldInjectAJAXHandler` is basically juts injecting JS to the web page, we should let developer inject whatever JS that address different issues that they want to fix.

Test Plan:
Test this snippet at <Playground />

```
<WebView
  url="http://www.facebook.com"
  injectedJavascriptIOS="document.body.style.border='solid 10px red'"
/>
```

2015-07-01 18:56:14 -08:00

..

WebView.android.js

[react_native] JS files from D2139723: [react_native] Set WebView user-agent from JS

2015-06-12 02:37:57 -08:00

WebView.ios.js

[WebView]: Kill shouldInjectAJAXHandler, and add injectedJavascriptIOS

2015-07-01 18:56:14 -08:00