Remove unnecessary utility function

src/dom.ts

@@ -15,12 +15,6 @@ export function contains(dom: Node, node: Node | null) {
   return node ? dom == node || dom.contains(node.nodeType != 1 ? node.parentNode : node) : false
 }
 
-export function deepActiveElement(doc: Document) {
-  let elt = doc.activeElement
-  while (elt && elt.shadowRoot) elt = elt.shadowRoot.activeElement
-  return elt
-}
-
 export function hasSelection(dom: HTMLElement, selection: SelectionRange): boolean {
   if (!selection.anchorNode) return false
   try {

src/domobserver.ts

@@ -2,8 +2,7 @@ import browser from "./browser"
 import {ContentView, ViewFlag} from "./contentview"
 import {EditorView} from "./editorview"
 import {editable, ViewUpdate, setEditContextFormatting, MeasureRequest} from "./extension"
-import {hasSelection, getSelection, DOMSelectionState, isEquivalentPosition,
-        deepActiveElement, dispatchKey, atElementStart} from "./dom"
+import {hasSelection, getSelection, DOMSelectionState, isEquivalentPosition, dispatchKey, atElementStart} from "./dom"
 import {DOMChange, applyDOMChange, applyDOMChangeInner} from "./domchange"
 import type {EditContext} from "./editcontext"
 import {Decoration} from "./decoration"
@@ -201,7 +200,7 @@ export class DOMObserver {
     let selection = getSelection(view.root)
     if (!selection) return false
     let range = browser.safari && (view.root as any).nodeType == 11 &&
-      deepActiveElement(this.dom.ownerDocument) == this.dom &&
+      view.root.activeElement == this.dom &&
       safariSelectionRangeHack(this.view, selection) || selection
     if (!range || this.selectionRange.eq(range)) return false
     let local = hasSelection(this.dom, range)