DevTools: preserve computed properties expansion on Computed Style re-rendering

third_party/WebKit/Source/devtools/front_end/elements/ComputedStyleWidget.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.
@@ skipping 131 matching lines @@
         swatch.setFormat(WebInspector.Color.detectColorFormat(color));
         return swatch;
     },
 
     /**
      * @param {?WebInspector.ComputedStyleModel.ComputedStyle} nodeStyle
      * @param {?WebInspector.CSSMatchedStyles} matchedStyles
      */
     _innerRebuildUpdate: function(nodeStyle, matchedStyles)
     {
+        /** @type {!Set<string>} */
+        var expandedProperties = new Set();
+        for (var treeElement of this._propertiesOutline.rootElement().children()) {
+            if (!treeElement.expanded)
+                continue;
+            var propertyName = treeElement[WebInspector.ComputedStyleWidget._propertySymbol].name;
+            expandedProperties.add(propertyName);
+        }
         this._propertiesOutline.removeChildren();
         this._linkifier.reset();
         var cssModel = this._computedStyleModel.cssModel();
         if (!nodeStyle || !matchedStyles || !cssModel)
             return;
 
         var uniqueProperties = nodeStyle.computedStyle.keysArray();
         uniqueProperties.sort(propertySorter);
 
         var propertyTraces = this._computePropertyTraces(matchedStyles);
@@ skipping 44 matching lines @@
             this._propertiesOutline.appendChild(treeElement);
 
             var trace = propertyTraces.get(propertyName);
             if (trace) {
                 var activeProperty = this._renderPropertyTrace(cssModel, matchedStyles, nodeStyle.node, treeElement, trace);
                 treeElement.listItemElement.addEventListener("mousedown", consumeEvent, false);
                 treeElement.listItemElement.addEventListener("dblclick", consumeEvent, false);
                 treeElement.listItemElement.addEventListener("click", handleClick.bind(null, treeElement), false);
                 var gotoSourceElement = propertyValueElement.createChild("div", "goto-source-icon");
                 gotoSourceElement.addEventListener("click", this._navigateToSource.bind(this, activeProperty));
+                if (expandedProperties.has(propertyName))

[dgozman, 2016/07/16 01:14:56]

Why is this inside "if (trace)" block?

[lushnikov, 2016/07/16 03:47:48]

Only properties with traces are expandable; others aren't.

+                    treeElement.expand();
             }
         }
 
         this._updateFilter(this._filterRegex);
 
         /**
          * @param {string} a
          * @param {string} b
          * @return {number}
          */
@@ skipping 123 matching lines @@
         var children = this._propertiesOutline.rootElement().children();
         for (var child of children) {
             var property = child[WebInspector.ComputedStyleWidget._propertySymbol];
             var matched = !regex || regex.test(property.name) || regex.test(property.value);
             child.hidden = !matched;
         }
     },
 
     __proto__: WebInspector.ThrottledWidget.prototype
 }