DevTools: Migrate from -webkit-user-modify to contenteditable

third_party/WebKit/Source/devtools/front_end/ui/InplaceEditor.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @unrestricted
  */
 UI.InplaceEditor = class {
   /**
    * @param {!Element} element
    * @param {!UI.InplaceEditor.Config=} config
@@ skipping 12 matching lines @@
     var element = editingContext.element;
     if (element.tagName === 'INPUT' && element.type === 'text')
       return element.value;
 
     return element.textContent;
   }
 
   setUpEditor(editingContext) {
     var element = editingContext.element;
     element.classList.add('editing');
+    element.setAttribute('contenteditable', 'plaintext-only');
 
     var oldTabIndex = element.getAttribute('tabIndex');
     if (typeof oldTabIndex !== 'number' || oldTabIndex < 0)
       element.tabIndex = 0;
     this._focusRestorer = new UI.ElementFocusRestorer(element);
     editingContext.oldTabIndex = oldTabIndex;
   }
 
   closeEditor(editingContext) {
     var element = editingContext.element;
     element.classList.remove('editing');
+    element.removeAttribute('contenteditable');
 
     if (typeof editingContext.oldTabIndex !== 'number')
       element.removeAttribute('tabIndex');
     else
       element.tabIndex = editingContext.oldTabIndex;
     element.scrollTop = 0;
     element.scrollLeft = 0;
   }
 
   cancelEditing(editingContext) {
@@ skipping 161 matching lines @@
     this.pasteHandler = pasteHandler;
   }
 
   /**
    * @param {function(!Event):string} postKeydownFinishHandler
    */
   setPostKeydownFinishHandler(postKeydownFinishHandler) {
     this.postKeydownFinishHandler = postKeydownFinishHandler;
   }
 };