Fix duplicate extensions in the profile loading error message

Source/devtools/front_end/profiler/ProfilesPanel.js

 /*
  * Copyright (C) 2008 Apple 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 565 matching lines @@
     _loadFromFile: function(file)
     {
         this._createFileSelectorElement();
 
         var profileType = this._findProfileTypeByExtension(file.name);
         if (!profileType) {
             var extensions = [];
             var types = WebInspector.ProfileTypeRegistry.instance.profileTypes();
             for (var i = 0; i < types.length; i++) {
                 var extension = types[i].fileExtension();
-                if (!extension)
+                if (!extension || extensions.indexOf(extension) !== -1)
                     continue;
                 extensions.push(extension);
             }
             WebInspector.console.log(WebInspector.UIString("Can't load file. Only files with extensions '%s' can be loaded.", extensions.join("', '")));
             return;
         }
 
         if (!!profileType.profileBeingRecorded()) {
             WebInspector.console.log(WebInspector.UIString("Can't load profile when other profile is recording."));
             return;
@@ skipping 741 matching lines @@
 importScript("HeapSnapshotCommon.js");
 importScript("HeapSnapshotProxy.js");
 importScript("HeapSnapshotDataGrids.js");
 importScript("HeapSnapshotGridNodes.js");
 importScript("HeapSnapshotView.js");
 importScript("ProfileLauncherView.js");
 importScript("CanvasProfileView.js");
 importScript("CanvasReplayStateView.js");
 
 WebInspector.ProfileTypeRegistry.instance = new WebInspector.ProfileTypeRegistry();