DevTools: all swatches get default focused element (reland with fix)

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

 // Copyright 2016 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.CSSShadowEditor = class extends UI.VBox {
   constructor() {
     super(true);
     this.registerRequiredCSS('ui/cssShadowEditor.css');
     this.contentElement.tabIndex = 0;
+    this.setDefaultFocusedElement(this.contentElement);
 
     this._typeField = this.contentElement.createChild('div', 'shadow-editor-field');
     this._typeField.createChild('label', 'shadow-editor-label').textContent = Common.UIString('Type');
     this._outsetButton = this._typeField.createChild('button', 'shadow-editor-button-left');
     this._outsetButton.textContent = Common.UIString('Outset');
     this._outsetButton.addEventListener('click', this._onButtonClick.bind(this), false);
     this._insetButton = this._typeField.createChild('button', 'shadow-editor-button-right');
     this._insetButton.textContent = Common.UIString('Inset');
     this._insetButton.addEventListener('click', this._onButtonClick.bind(this), false);
 
@@ skipping 397 matching lines @@
 };
 
 /** @type {number} */
 UI.CSSShadowEditor.maxRange = 20;
 /** @type {string} */
 UI.CSSShadowEditor.defaultUnit = 'px';
 /** @type {number} */
 UI.CSSShadowEditor.sliderThumbRadius = 6;
 /** @type {number} */
 UI.CSSShadowEditor.canvasSize = 88;