DevTools: [regression] entering invalid property value in the styles sidebar results in exception.

Source/devtools/front_end/elements/StylesSidebarPane.js

Index: Source/devtools/front_end/elements/StylesSidebarPane.js
diff --git a/Source/devtools/front_end/elements/StylesSidebarPane.js b/Source/devtools/front_end/elements/StylesSidebarPane.js
index 4e72e256873ee2f284a4f87b117fb41db17c9a9f..d2a8e3540486e30a686d779684a420001cba17f6 100644
--- a/Source/devtools/front_end/elements/StylesSidebarPane.js
+++ b/Source/devtools/front_end/elements/StylesSidebarPane.js
@@ -2610,7 +2610,6 @@ WebInspector.StylePropertyTreeElement.prototype = {
      */
     editingEnded: function(context)
     {
-        delete this._originalPropertyText;
         this._resetMouseDownElement();
 
         this.setExpandable(context.hasChildren);
@@ -2638,12 +2637,14 @@ WebInspector.StylePropertyTreeElement.prototype = {
 
     _revertStyleUponEditingCanceled: function()
     {
-        if (this._propertyHasBeenEditedIncrementally)
+        if (this._propertyHasBeenEditedIncrementally) {
             this.applyStyleText(this._originalPropertyText, false);
-        else if (this._newProperty)
+            delete this._originalPropertyText;
+        } else if (this._newProperty) {
             this.treeOutline.removeChild(this);
-        else
+        } else {
             this.updateTitle();
+        }
     },
 
     /**