DevTools: Use View.registerRequiredCSS() in View-based web components

Source/devtools/front_end/elements/Spectrum.js

 /*
  * Copyright (C) 2011 Brian Grinstead All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 15 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 /**
  * @constructor
  * @extends {WebInspector.VBox}
  */
 WebInspector.Spectrum = function()
 {
     WebInspector.VBox.call(this, true);
-    this.contentElement.appendChild(WebInspector.View.createStyleElement("elements/spectrum.css"));
+    this.registerRequiredCSS("elements/spectrum.css");
     this.contentElement.tabIndex = 0;
 
     this._draggerElement = this.contentElement.createChild("div", "spectrum-color");
     this._dragHelperElement = this._draggerElement.createChild("div", "spectrum-sat fill").createChild("div", "spectrum-val fill").createChild("div", "spectrum-dragger");
 
     this._sliderElement = this.contentElement.createChild("div", "spectrum-hue");
     this.slideHelper = this._sliderElement.createChild("div", "spectrum-slider");
 
     var rangeContainer = this.contentElement.createChild("div", "spectrum-range-container");
     var alphaLabel = rangeContainer.createChild("label");
@@ skipping 408 matching lines @@
 
 WebInspector.ColorSwatch.prototype = {
     /**
      * @param {string} colorString
      */
     setColorString: function(colorString)
     {
         this._swatchInnerElement.style.backgroundColor = colorString;
     }
 }