[Cocoa] Rename a bundle form delegate method
https://bugs.webkit.org/show_bug.cgi?id=132221

Reviewed by Adele Peterson.

* WebProcess/InjectedBundle/API/Cocoa/WKWebProcessPlugInFormDelegatePrivate.h: Renamed.
* WebProcess/InjectedBundle/API/mac/WKWebProcessPlugInBrowserContextController.mm:
(-[WKWebProcessPlugInBrowserContextController _setFormDelegate:]): Check for the method
under the old (“new”) name and under the new name.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@167846 268f45cc-cd09-0410-ab3c-d52691b4dbfc