WKWebView should provide some means of handling render process termination.

[Eugene But]

Summary:
Under the new WebKit framework in iOS8, content is rendered in a process separate from the application that owns the WKWebView instance. If the render process is terminated due to memory pressure, or crashes, the WKWebView(s) that it was rendering for are not notified in any way and don't have any way to reload their contents.

Ideally there would be a WKWebViewDelegate protocol that would include something like a -shouldReloadAfterRenderFailure method where the delegate can return YES or NO to trigger  re-rendering the page, spawning a new render process as needed.

Steps to Reproduce:
1. Create an application that uses a WKWebView
2. Induce the WKWebView's render process to crash or be terminated
3. Observe that the WKWebView is blank and doesn't reload.
(This is the behavior described by engineers at WWDC).

Expected Results:
The WKWebView gets notified that there was a render failure. F.e. by making the following method public:
- (void)_webViewWebProcessDidCrash:(WKWebView *)webView;

Actual Results:
The WKWebView doesn't get notified.

[Eugene But]

Radar ID: 17210335

[Stuart Morgan]

*** This bug has been marked as a duplicate of bug 146085 ***