Remove WebKit1 header includes from WebKit2

Remove WebKit1 header includes from WebKit2
https://bugs.webkit.org/show_bug.cgi?id=129824

Reviewed by Dan Bernstein.

* UIProcess/mac/WKFullScreenWindowController.mm:
(makeResponderFirstResponderIfDescendantOfView):
Add a new function instead of calling an NSWindow category method that's defined in WebKit1.

(-[WKFullScreenWindowController enterFullScreen:]):
(-[WKFullScreenWindowController finishedEnterFullScreenAnimation:]):
(-[WKFullScreenWindowController finishedExitFullScreenAnimation:]):
Call makeResponderFirstResponderIfDescendantOfView.

* WebProcess/WebCoreSupport/mac/WebDragClientMac.mm:
Remove unused WebKit1 header import.

* WebProcess/WebCoreSupport/mac/WebEditorClientMac.mm:
(WebKit::WebEditorClient::documentFragmentFromAttributedString):
Change a category to be on NSObject instead of WebResource.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@165218 268f45cc-cd09-0410-ab3c-d52691b4dbfc