Remove code to update block selection

Remove code to update block selection
https://bugs.webkit.org/show_bug.cgi?id=178843

Reviewed by Tim Horton.

Removes code for updating block selection, which has been disabled.
This code is being slowly pruned to avoid regressions and accidental removal of code that is being used.

* Platform/spi/ios/UIKitSPI.h:
* UIProcess/PageClient.h:
* UIProcess/WebPageProxy.h:
* UIProcess/WebPageProxy.messages.in:
* UIProcess/ios/PageClientImplIOS.h:
* UIProcess/ios/PageClientImplIOS.mm:
(WebKit::PageClientImpl::didUpdateBlockSelectionWithTouch): Deleted.
* UIProcess/ios/WKContentViewInteraction.h:
* UIProcess/ios/WKContentViewInteraction.mm:
(toSelectionHandlePosition): Deleted.
(-[WKContentView _didUpdateBlockSelectionWithTouch:withFlags:growThreshold:shrinkThreshold:]): Deleted.
(-[WKContentView changeBlockSelectionWithTouchAt:withSelectionTouch:forHandle:]): Deleted.
* UIProcess/ios/WebPageProxyIOS.mm:
(WebKit::WebPageProxy::updateBlockSelectionWithTouch): Deleted.
(WebKit::WebPageProxy::didUpdateBlockSelectionWithTouch): Deleted.
* WebProcess/WebPage/WebPage.h:
* WebProcess/WebPage/WebPage.messages.in:
* WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::shouldExpand): Deleted.
(WebKit::WebPage::changeBlockSelection): Deleted.
(WebKit::WebPage::updateBlockSelectionWithTouch): Deleted.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@224029 268f45cc-cd09-0410-ab3c-d52691b4dbfc