There's no API for the UI process to find out when the web process crashes. We should add one! Probably adding a WKPageProcessDidExitCallback member to WKPageLoaderClient is the way to go for now (though we might move it to wherever the DidBecome[Un]ResponsiveCallbacks go, once they move to a new client).
Created attachment 62694 [details]
Attachment 62694 [details] did not pass style-queue:
Failed to run "['WebKitTools/Scripts/check-webkit-style']" exit_code: 1
WebKit2/UIProcess/API/C/WKPage.h:96: Extra space between WKPageProcessDidExitCallback and processDidExit [whitespace/declaration] 
Total errors found: 1 in 5 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Committed r64132: <http://trac.webkit.org/changeset/64132>