DevTools: ensure to show the same Popover object only once.

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

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 65 matching lines @@
     /**
      * @param {?WebInspector.Widget} view
      * @param {!Element} contentElement
      * @param {!Element|!AnchorBox} anchor
      * @param {?number=} preferredWidth
      * @param {?number=} preferredHeight
      * @param {?WebInspector.Popover.Orientation=} arrowDirection
      */
     _innerShow: function(view, contentElement, anchor, preferredWidth, preferredHeight, arrowDirection)
     {
-        if (this._disposed)
+        if (this._disposed || WebInspector.Popover._popover === this)
             return;
         this._contentElement = contentElement;
 
         // This should not happen, but we hide previous popup to be on the safe side.
         if (WebInspector.Popover._popover)
             WebInspector.Popover._popover.hide();
         WebInspector.Popover._popover = this;
 
         var document = anchor instanceof Element ? anchor.ownerDocument : contentElement.ownerDocument;
         var window = document.defaultView;
@@ skipping 321 matching lines @@
             this._resetHoverTimer();
         }
     }
 }
 
 /** @enum {string} */
 WebInspector.Popover.Orientation = {
     Top: "top",
     Bottom: "bottom"
 }