Remove unused editing related member functions from WebViewClient

LayoutTests/editing/pasteboard/nested-blocks-with-text-area-expected.txt

-EDITING DELEGATE: shouldBeginEditingInDOMRange:range from 0 of BODY > HTML > #document to 5 of BODY > HTML > #document
-EDITING DELEGATE: webViewDidBeginEditing:WebViewDidBeginEditingNotification
-EDITING DELEGATE: webViewDidChangeSelection:WebViewDidChangeSelectionNotification
-EDITING DELEGATE: shouldChangeSelectedDOMRange:range from 0 of BODY > HTML > #document to 0 of BODY > HTML > #document toDOMRange:range from 1 of #text > BODY > HTML > #document to 2 of BODY > HTML > #document affinity:NSSelectionAffinityDownstream stillSelecting:FALSE
 EDITING DELEGATE: webViewDidChangeSelection:WebViewDidChangeSelectionNotification
 EDITING DELEGATE: webViewDidChangeSelection:WebViewDidChangeSelectionNotification
-EDITING DELEGATE: shouldChangeSelectedDOMRange:range from 5 of BODY > HTML > #document to 5 of BODY > HTML > #document toDOMRange:range from 1 of #text > DIV > DIV > BODY > HTML > #document to 1 of #text > DIV > DIV > BODY > HTML > #document affinity:NSSelectionAffinityDownstream stillSelecting:FALSE
+EDITING DELEGATE: webViewDidChangeSelection:WebViewDidChangeSelectionNotification
 EDITING DELEGATE: webViewDidChangeSelection:WebViewDidChangeSelectionNotification
 EDITING DELEGATE: webViewDidChange:WebViewDidChangeNotification
 | "
 These demonstrate 11475: the '\n's at the end of the fragment should be unrendered."
 | <br>
 | <div>
 |   "This test checks that pasing in a combination of nested blocks where one starts with a text field doesn't crash or fail assertions."
 | "
 "
 | <div>
 |   "
 "
 |   <div>
 |     "
 "
 |     <textarea>
 |       this.value=" "
 |       " "
 |       <shadow:root>
 |         <div>
 |           " "
 |     " 
 "
 |     "x<#selection-caret>"
 |     "
 "
 | "
 
 "