DevTools: convert a few more icons to UI.Icon.

third_party/WebKit/Source/devtools/front_end/elements/StylesSidebarPane.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * 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.
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   }
 
   _resetMouseDownElement() {
     if (this._parentPane) {
       delete this._parentPane._mouseDownTreeElement;
       delete this._parentPane._mouseDownTreeElementIsName;
       delete this._parentPane._mouseDownTreeElementIsValue;
     }
   }
 
+  /**
+   * @override
+   */
+  onexpand() {
+    this._updateExpandElement();
+  }
+
+  /**
+   * @override
+   */
+  oncollapse() {
+    this._updateExpandElement();
+  }
+
+  _updateExpandElement() {
+    if (this.expanded)
+      this._expandElement.setIconType('smallicon-triangle-bottom');
+    else
+      this._expandElement.setIconType('smallicon-triangle-right');
+  }
+
   updateTitle() {
     this._updateState();
-    this._expandElement = createElement('span');
-    this._expandElement.className = 'expand-element';
+    this._expandElement = UI.Icon.create('smallicon-triangle-right', 'expand-icon');
 
     var propertyRenderer =
         new Elements.StylesSidebarPropertyRenderer(this._style.parentRule, this.node(), this.name, this.value);
     if (this.property.parsedOk) {
       propertyRenderer.setColorHandler(this._processColor.bind(this));
       propertyRenderer.setBezierHandler(this._processBezier.bind(this));
       propertyRenderer.setShadowHandler(this._processShadow.bind(this));
     }
 
     this.listItemElement.removeChildren();
@@ skipping 932 matching lines @@
   }
 
   /**
    * @override
    * @return {!UI.ToolbarItem}
    */
   item() {
     return this._button;
   }
 };